Academic literature on the topic 'Statistical size effect'

Manufacturing process based imperfections can reduce the theoretical fatigue strength since they can be considered as pre-existent microcracks. The statistical distribution of fatigue fracture initiating defect sizes also varies with the highly-stressed volume, since the probability of a larger highly-stressed volume to inherit a potentially critical defect is elevated. This fact is widely known by the scientific community as the statistical size effect. The assessment of this effect within this paper is based on the statistical distribution of defect sizes in a reference volume V 0 compared to an arbitrary enlarged volume V α . By implementation of the crack resistance curve in the Kitagawa–Takahashi diagram, a fatigue assessment model, based on the volume-dependent probability of occurrence of inhomogeneities, is set up, leading to a multidimensional fatigue assessment map. It is shown that state-of-the-art methodologies for the evaluation of the statistical size effect can lead to noticeable over-sizing in fatigue design of approximately 10 % . On the other hand, the presented approach, which links the statistically based distribution of defect sizes in an arbitrary highly-stressed volume to a crack-resistant dependent Kitagawa–Takahashi diagram leads to a more accurate fatigue design with a maximal conservative deviation of 5 % to the experimental validation data. Therefore, the introduced fatigue assessment map improves fatigue design considering the statistical size effect of lightweight aluminium cast alloys.

Objective: To describe the concept of statistical power as related to comparative interventions and how various factors, including sample size, affect statistical power.Background: Having a sufficiently sized sample for a study is necessary for an investigation to demonstrate that an effective treatment is statistically superior. Many researchers fail to conduct and report a priori sample-size estimates, which then makes it difficult to interpret nonsignificant results and causes the clinician to question the planning of the research design.Description: Statistical power is the probability of statistically detecting a treatment effect when one truly exists. The α level, a measure of differences between groups, the variability of the data, and the sample size all affect statistical power.Recommendations: Authors should conduct and provide the results of a priori sample-size estimations in the literature. This will assist clinicians in determining whether the lack of a statistically significant treatment effect is due to an underpowered study or to a treatment's actually having no effect.

Statistical power is the ability to detect a significant effect, given that the effect actually exists in a population. Like most statistical concepts, statistical power tends to induce cognitive dissonance in hepatology researchers. However, planning for statistical power by ana priorisample size calculation is of paramount importance when designing a research study. There are five specific empirical components that make up ana priorisample size calculation: the scale of measurement of the outcome, the research design, the magnitude of the effect size, the variance of the effect size, and the sample size. A framework grounded in the phenomenon of isomorphism, or interdependencies amongst different constructs with similar forms, will be presented to understand the isomorphic effects of decisions made on each of the five aforementioned components of statistical power.

OBJECTIVE: Effect size (ES) is the statistical measure which quantifies the strength of a phenomenon and is commonly applied to observational and interventional studies. The aim of this review was to describe the conceptual basis of this measure, including its application, calculation and interpretation.RESULTS: As well as being used to detect the magnitude of the difference between groups, to verify the strength of association between predictor and outcome variables, to calculate sample size and power, ES is also used in meta-analysis. ES formulas can be divided into these categories: I – Difference between groups, II – Strength of association, III – Risk estimation, and IV – Multivariate data. The d value was originally considered small (0.20 > d ≤ 0.49), medium (0.50 > d≤ 0.79) or large (d ≥ 0.80); however, these cut-off limits are not consensual and could be contextualized according to a specific field of knowledge. In general, a larger score implies that a larger difference was detected.CONCLUSION: The ES report, in conjunction with the confidence interval and P value, aims to strengthen interpretation and prevent the misinterpretation of data, and thus leads to clinical decisions being based on scientific evidence studies.

To help address the knowledge gap between science and practice this study explores the possible positive benefits of using a more pedagogical effect size estimate when presenting statistical relationships. Traditional presentation has shown limitations with major downsides being that scientific findings are misinterpreted or misunderstood even by professionals. This study explores the possible effects of the non-traditional effect size estimate Common Language Effect Size (CLES) on different training outcomes for HR professionals. This study also explores the possible effect of cognitive system preference on training outcomes. Results show no overall effect of CLES on either training outcomes or cognitive system. A positive effect of CLES on training outcome is found at the subfactor level showing a significant effect. The results can be interpreted that non-traditional effect size estimates have a limited effect on training outcomes. This small but valuable piece to bridge the gap of knowledge is discussed.

The present article describes a method to quantify the magnitude of the differences between two measures and/or the degree of the effect of a variable about criteria, and it is named likethe effect size measure, d. Use it use in research and applied contexts provides a quitedescriptive complementary information, improving the interpretation of the results obtained bythe traditional methods that emphasize the statistical significance. Severa) forms there are of interpreting the d, and an example taken of an experimental research, is presented to clarify the concepts and necessary calculations. This method is not robust to sorne conditions that they candistort its interpretation, for example, the non normality of the data; alternative methods are mentioned to the statistical d. We ending with sorne conclusions that will notice about the appropriate use of it.
El presente artículo describe un método para cuantificar la magnitud de las diferencias entredos mediciones y/o el grado del efecto de una variable sobre un criterio, y es llamado lamedida de la magnitud del efecto, de su uso en contextos de investigación y aplicados proporciona un información complementaria bastante descriptiva, mejorando la interpretaciónde los resultados obtenidos por los métodos tradicionales que enfatizan la significación estadística. Existen varias formas de interpretar el estadístico d, y se presenta un ejemplo,tomado de una investigación experimental, para aclarar los conceptos y cálculos necesarios.Este método no es robusto a ciertas condiciones que pueden distorsionar su interpretación, por ejemplo, la no normalidad de los datos entre otros; se mencionan métodos alternativos alestadístico d. Finalizamos con unas conclusiones que advierten sobre su apropiado uso.

L'indentation instrumentée est un outil pratique et puissant pour sonder les propriétés mécaniques des matériaux à petite échelle. Cependant, plusieurs erreurs (rugosité de surface, effet de taille d’indentation, la détermination de premier point de contact, etc.) affectent l'essai d’indentation instrumentée (e.g. non reproductibilité de la courbe d’indentation) et conduisent à des imprécisions dans la détermination des propriétés mécaniques des matériaux analysés. Une approche originale est développée dans cette thèse pour la caractérisation précise des propriétés mécaniques des matériaux. Cette approche fondée sur une analyse statistique des courbes d’indentation avec la prise en compte d’erreur dans la détermination du premier point de contact et des effets de la rugosité de surface. L’approche est basée sur une minimisation de la distance (défini comme l'erreur de la profondeur de contact initiale) entre l’ensemble des courbes expérimentales et celles simulées par le modèle de Bernhard de manière à générer une courbe maitresse « unique » représentative du faisceau de courbes expérimentales. La méthode proposée permet de calculer à partir de cette courbe maitresse la macro-dureté et le module d’Young du matériau en tenant compte des erreurs dues à la rugosité de surface et à l'effet de taille en indentation pour les faibles profondeurs de pénétration. La robustesse de la méthode est prouvée par son application à différents groupes d’échantillons, i.e. panels de matériaux à propriétés mécaniques diverses, différents traitements de surface (polissage, sablage) et différentes pointes d’indentation permettant de générer différents états de contraintes locaux. Une liaison quantitative entre la rugosité de surface et l'écart type de l'erreur de la profondeur de contact initiale est établie grâce à une analyse multi- échelle de la rugosité de la surface. La méthode proposée permet de caractériser les propriétés mécaniques des matériaux sans avoir recours à la préparation de surface pouvant potentiellement altérer ses propriétés (e.g. génération de contraintes résiduelles, contamination de surface…)
Instrumented indentation is a practical and powerful tool for probing the mechanical properties of materials at small scales. However, several errors (surface roughness, indentation size effect, determination of first contact point, etc…) affect the instrumented indentation testing (e.g. the low reproducibility of the indentation curves) and lead to inaccuracies in the determination of mechanical properties of materials analyzed. An original approach is developed in this thesis for the accurate characterization of the mechanical properties of materials. This approach is established by a statistical analysis of the indentation curves with taking account of error in determining the first contact point and effects of the surface roughness. This approach is basing on a minimization of the distance (defined as the initial contact depth error) between the experimental indentation curves and the ones simulated with Bernhard’s model in order to generate a “unique” representative curve which enables to represent all the experimental curves. The proposed method permits to calculate the macro-hardness and the Young’s modulus of materials from this representative curve with the consideration of the errors due to the surface roughness and the indentation size effect for shallow penetration. The robustness of the method is proved by its application to different groups of specimens, i.e. different materials with various mechanical properties, different surface preparation methods (polishing, sandblasting) and different indenter tips to generate different states of local stresses. A quantitative link between the surface roughness and the standard deviation of initial contact depth error is established by a multi-scale surface roughness analyzing. The proposed method enables to characterize the mechanical properties of materials without resorting to the surface preparation which may potentially alter its properties (e.g. generation of residual stresses, surface contamination ...)

Patient reported outcomes (PROs) are becoming increasingly important in cancer studies, particularly with the emphasis on patient centered outcome research. However, multiple PROs, using different scales, with different directions of favorability are often used within a trial, making interpretation difficult. To enhance interpretability, we propose the use of a standardized effect size graph, which shows all PROs from a study on the same figure, on the same scale. Plotting standardized effects with their 95% confidence intervals (CIs) on a single graph clearly showing the null value conveys a comprehensive picture of trial results. We demonstrate how to create such a graph using data from a randomized controlled trial that measured 12 PROs at two time points. The 24 effect sizes and CIs are shown on one graph and clearly indicate that the intervention is effective and sustained.

The scaling of specific cutting energy is studied when micro-cutting ductile metals. A unified framework for understanding the scaling in specific cutting energy is first presented by viewing the cutting force as a combination of constant, increasing, and decreasing force components, the independent variable being the uncut chip thickness. Then, an attempt is made to isolate the constant force component by performing high rake angle orthogonal cutting experiments on OFHC Copper. The data shows a trend towards a constant cutting force component as the rake angle is increased. In order to understand the source of this constant force component the chip-root is investigated. By quickly stopping the spindle at low cutting speeds, the chip is frozen and the chip-workpiece interface is examined in a scanning electron microscope. Evidence of ductile tearing ahead of the cutting tool is seen at low and high rake angles. At higher cutting speeds a quick-stop device is used to obtain chip-roots. These experiments also clearly indicate evidence of ductile fracture ahead of the cutting tool in both OFHC Copper and Al-2024 T3. To model the cutting process with ductile fracture leading to material separation the finite element method is used. The model is implemented in a commercial finite element software using the explicit formulation. Material separation is modeled via element failure. The model is then validated using the measured cutting and thrust forces and used to study the energy consumed in cutting. As the thickness of layer removed is reduced the energy consumed in material separation becomes important. Simulations also show that the stress state ahead of the tool is favorable for ductile fracture to occur. Ductile fracture in three locations in an interface zone at the chip root is seen while cutting with edge radius tool. A hypothesis is advanced wherein an element gets wrapped around the tool edge and is stretched in two directions leading to fracture. The numerical model is then used to study the difference in stress state and energy consumption between a sharp tool and a tool with a non-zero edge radius.

The idea underlying the present study was to apply twisting in order to introduce different levels of transverse pressure. The modified structure affected both the bonding level and the evolution of the damage in the yarn. In order to isolate this effect in a broader context, additional parameters were included in the experiment design, namely effects of loading rate, specimen length and filament diameter (directly linked to the fineness of the yarn). These factors have been studied in various contexts by several authors. Some related studies on involved factors will be briefly reviewed.

A brittle thin film bonded to a substrate is common in MEMS components. At the edge of the interface, high stress gradients exist. It has been observed that mechanical strengthening of the thin film with decreasing film size occurs due to two constraints, namely, the microstructural constraint and the geometrical constraint. Consideration of both these constraints is required to properly predict the size effect impact on the strength of a brittle thin film. In this paper, a statistical approach is developed to predict the size effect of a brittle thin film on a substrate.

The intent of this work is to derive a physically motivated mathematical form for the gradient plasticity that can be used to interpret the size effects observed experimentally. This paper addresses a possible, yet simple, link between the Taylor’s model of dislocation hardening and the strain gradient plasticity. Evolution equations for the densities of statistically stored dislocations and geometrically necessary dislocations are used to establish this linkage. The dislocation processes of generation, motion, immobilization, recovery, and annihilation are considered in which the geometric obstacles contribute to the storage of statistical dislocations. As a result a physically sound relation for the material length scale parameter is obtained as a function of the course of plastic deformation, grain size, and a set of macroscopic and microscopic physical parameters. The proposed model gives good predictions of the size effect in micro-bending tests of thin films and micro-torsion tests of thin wires.

The response of quasi-brittle materials is greatly influenced by their microstructural architecture and variations. To model such statistical variability, Statistical Volume Elements (SVEs) are used to derive a scalar fracture strength for domains populated with microcracks. By employing the moving window approach the probability density function and covariance function of the scalar fracture strength field are obtained. The Karhunen-Loève method is used to generate realizations of fracture strength that are consistent with the SVE-derived statistics. The effect of homogenization scheme, through the size of SVE, on fracture pattern is studied by using an asynchronous spacetime discontinuous Galerkin (aSDG) finite element method, where cracks are exactly tracked by the method’s adaptive operations.

This paper correlates as-received relief valve test results with current inspection intervals and presents conclusions based on statistical analysis. During the past three year period over 500 used valve proof test records from a site population of 3500 safety relief valves were acquired and reviewed. Collection and analysis of spring-loaded relief valve test data continues with the goal being to increase the test intervals within guidelines, reduce costs, and maintain safety margins. Based on current test intervals of 1–7 years, time in service appears to have a minimal effect on valve performance. Seat material and inlet size are identified as having a statistically significant impact on valve performance. An increase in TP/SP of 1–2% per year was noted for soft seated, small inlet sizes. Photographs of failed valve internals and discussion of failure causes are included.

Titania pigments are used in molding compounds as a means to improve opacity by increasing the scattering efficiency of the medium and to develop new applications such as liquid crystal displays (LCD) and light emitting diodes (LED). The characteristics of the injection molded products are a function of molding parameters such as gate location and shear rate. In this study, quantitative measures of the particle distribution of titania pigments in polymer composites have been experimentally determined, including area fraction, average diameter, and diameter volume. A 2 × 3 × 3 ANOVA test has been conducted to assess the statistical significance of these parameters. This study deals with the size and spatial distribution of the particles. The important parameters calculated based on the Feret’s diameter are diameter-volume (dv), diameter-number (dn), and area fraction (AF). The term diameter-volume (dv) has been used to give greater significance to the large particles and thus ‘large’ indicates more and/or larger particles. The parameters have been calculated by using Image-J image processing software. MINITAB has been used to assess the statistical significance of these parameters. The results show that titania particles are not uniformly distributed within the final molded parts and they vary along the molding (longitudinal) and transverse directions of plastic flow. The difference of pigment area fraction and diameter volume at different locations within a final molded part has a significant effect on the percentage reflectance of the surface.

Standards have traditionally required that fracture toughness specimens be the full thickness of the base material. However, this requirement may be unnecessary, especially if minimum specimen size dimensions based on plastic zone are met and the subsized specimens are statistically adjusted for the size effect. The current paper presents the results for full-thickness proportional Single Edge Notched Bending (SENB) specimens according to BS7448-1 that are 25 mm by 50 mm in cross-section and then compares these results to specimens of the same material that are 10 mm by 20 mm in cross section. The result is that for a temperature near the lower portion of the transition curve (−60°C to −70°C), the subsize specimens are in very good agreement. These results hold for two different loading rates. After correction for statistical size effect, the fracture toughnesses of the subsize specimens are within 10% of the full-size specimens. This is conservative. The difference is attributed to the statistical nature of fracture in the transition region.

Many students struggle with mathematics in late elementary school, particularly on the topic of fractions. In a best evidence syntheses of research on increasing achievement in elementary school mathematics, Pelligrini et al. (2018) highlighted tutoring as a way to help students. Online tutoring is attractive because costs may be lower and logistics easier than with face-to-face tutoring. Cignition developed an approach that combines online 1:1 tutoring with a fractions game, called FogStone Isle. The game provides students with additional learning opportunities and provides tutors with information that they can use to plan tutoring sessions. A randomized controlled trial investigated the research question: Do students who participate in online tutoring and a related mathematical game learn more about fractions than students who only have access to the game? Participants were 144 students from four schools, all serving low-income students with low prior mathematics achievement. In the Treatment condition, students received 20-25 minute tutoring sessions twice per week for an average of 18 sessions and also played the FogStone Isle game. In the Control condition, students had access to the game, but did not play it often. Control students did not receive tutoring. Students were randomly assigned to condition after being matched on pre-test scores. The same diagnostic assessment was used as a pre-test and as a post-test. The planned analysis looked for differences in gain scores ( post-test minus pre-test scores) between conditions. We conducted a t-test on the aggregate gain scores, comparing conditions; the results were statistically significant (t = 4.0545, df = 132.66, p-value < .001). To determine an effect size, we treated each site as a study in a meta-analysis. Using gain scores, the effect size was g=+.66. A more sophisticated treatment of the pooled standard deviation resulted in a corrected effect size of g=.46 with a 95% confidence interval of [+.23,+.70]. Students who received online tutoring and played the related Fog Stone Isle game learned more; our research found the approach to be efficacious. The Pelligrini et al. (2018) meta-analysis of elementary math tutoring programs found g = .26 and was based largely on face-to-face tutoring studies. Thus, this study compares favorably to prior research on face-to-face mathematics tutoring with elementary students. Limitations are discussed; in particular, this is an initial study of an intervention under development. Effects could increase or decrease as development continues and the program scales. Although this study was planned long before the current pandemic, results are particularly timely now that many students are at home under shelter-in-place orders due to COVID-19. The approach taken here is feasible for students at home, with tutors supporting them from a distance. It is also feasible in many other situations where equity could be addressed directly by supporting students via online tutors.

This technical report presents two applications of the GenCade model to simulate long-term shoreline evolution along the Delaware Coast driven by waves, inlet sediment transport, and longshore sediment transport. The simulations also include coastal protection practices such as periodic beach fills, post-storm nourishment, and sand bypassing. Two site-specific GenCade models were developed: one is for the coasts adjacent to the Indian River Inlet (IRI) and another is for Fenwick Island. In the first model, the sediment exchanges among the shoals and bars of the inlet were simulated by the Inlet Reservoir Model (IRM) in the GenCade. An inlet sediment transfer factor (γ) was derived from the IRM to quantify the capability of inlet sediment bypassing, measured by a rate of longshore sediments transferred across an inlet from the updrift side to the downdrift side. The second model for the Fenwick Island coast was validated by simulating an 11-y ear-long shoreline evolution driven by longshore sediment transport and periodic beach fills. Validation of the two models was achieved through evaluating statistical errors of simulations. The effects of the sand bypassing operation across the IRI and the beach fills in Fenwick Island were examined by comparing simulation results with and without those protection practices. Results of the study will benefit planning and management of coastal sediments at the sites.

Snow is a critical water resource for much of the U.S. and failure to account for changes in climate could deleteriously impact military assets. In this study, we produced historical and future snow trends through modeling at three military sites (in Washington, Colorado, and North Dakota) and the Western U.S. For selected rivers, we performed seasonal trend analysis of discharge extremes. We calculated flood frequency curves and estimated the probability of occurrence of future annual maximum daily rainfall depths. Additionally, we generated intensity-duration-frequency curves (IDF) to find rainfall intensities at several return levels. Generally, our results showed a decreasing trend in historical and future snow duration, rain-on-snow events, and snowmelt runoff. This decreasing trend in snowpack could reduce water resources. A statistically significant increase in maximum streamflow for most rivers at the Washington and North Dakota sites occurred for several months of the year. In Colorado, only a few months indicated such an increase. Future IDF curves for Colorado and North Dakota indicated a slight increase in rainfall intensity whereas the Washington site had about a twofold increase. This increase in rainfall intensity could result in major flood events, demonstrating the importance of accounting for climate changes in infrastructure planning.

The summative external evaluation report described the program's impact on faculty and students participating in recitation sessions and active teaching professional development sessions over two years. Student persistence and retention in engineering courses continue to be a challenge in undergraduate education, especially for students underrepresented in engineering disciplines. The program's goal was to use peer-facilitated instruction in core engineering courses known to have high attrition rates to retain underrepresented students, especially women, in engineering to diversify and broaden engineering participation. Knowledge generated around using peer-facilitated instruction at two-year colleges can improve underrepresented students' success and participation in engineering across a broad range of institutions. Students in the program participated in peer-facilitated recitation sessions linked to fundamental engineering courses, such as engineering analysis, statics, and dynamics. These courses have the highest failure rate among women and underrepresented minority students. As a mixed-methods evaluation study, student engagement was measured as students' comfort with asking questions, collaboration with peers, and applying mathematics concepts. SPSS was used to analyze pre-and post-surveys for statistical significance. Qualitative data were collected through classroom observations and focus group sessions with recitation leaders. Semi-structured interviews were conducted with faculty members and students to understand their experiences in the program. Findings revealed that women students had marginalization and intimidation perceptions primarily from courses with significantly more men than women. However, they shared numerous strategies that could support them towards success through the engineering pathway. Women and underrepresented students perceived that they did not have a network of peers and faculty as role models to identify within engineering disciplines. The recitation sessions had a positive social impact on Hispanic women. As opportunities to collaborate increased, Hispanic womens' social engagement was expected to increase. This social engagement level has already been predicted to increase women students' persistence and retention in engineering and result in them not leaving the engineering pathway. An analysis of quantitative survey data from students in the three engineering courses revealed a significant effect of race and ethnicity for comfort in asking questions in class, collaborating with peers outside the classroom, and applying mathematical concepts. Further examination of this effect for comfort with asking questions in class revealed that comfort asking questions was driven by one or two extreme post-test scores of Asian students. A follow-up ANOVA for this item revealed that Asian women reported feeling excluded in the classroom. However, it was difficult to determine whether these differences are stable given the small sample size for students identifying as Asian. Furthermore, gender differences were significant for comfort in communicating with professors and peers. Overall, women reported less comfort communicating with their professors than men. Results from student metrics will inform faculty professional development efforts to increase faculty support and maximize student engagement, persistence, and retention in engineering courses at community colleges. Summative results from this project could inform the national STEM community about recitation support to further improve undergraduate engineering learning and educational research.

Objectives. To assess the comparative effectiveness and potential harms of cervical ripening in the outpatient setting (vs. inpatient, vs. other outpatient intervention) and of fetal surveillance when a prostaglandin is used for cervical ripening. Data sources. Electronic databases (Ovid® MEDLINE®, Embase®, CINAHL®, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews) to July 2020; reference lists; and a Federal Register notice. Review methods. Using predefined criteria and dual review, we selected randomized controlled trials (RCTs) and cohort studies of cervical ripening comparing prostaglandins and mechanical methods in outpatient versus inpatient settings; one outpatient method versus another (including placebo or expectant management); and different methods/protocols for fetal surveillance in cervical ripening using prostaglandins. When data from similar study designs, populations, and outcomes were available, random effects using profile likelihood meta-analyses were conducted. Inconsistency (using I2) and small sample size bias (publication bias, if ≥10 studies) were assessed. Strength of evidence (SOE) was assessed. All review methods followed Agency for Healthcare Research and Quality Evidence-based Practice Center methods guidance. Results. We included 30 RCTs and 10 cohort studies (73% fair quality) involving 9,618 women. The evidence is most applicable to women aged 25 to 30 years with singleton, vertex presentation and low-risk pregnancies. No studies on fetal surveillance were found. The frequency of cesarean delivery (2 RCTs, 4 cohort studies) or suspected neonatal sepsis (2 RCTs) was not significantly different using outpatient versus inpatient dinoprostone for cervical ripening (SOE: low). In comparisons of outpatient versus inpatient single-balloon catheters (3 RCTs, 2 cohort studies), differences between groups on cesarean delivery, birth trauma (e.g., cephalohematoma), and uterine infection were small and not statistically significant (SOE: low), and while shoulder dystocia occurred less frequently in the outpatient group (1 RCT; 3% vs. 11%), the difference was not statistically significant (SOE: low). In comparing outpatient catheters and inpatient dinoprostone (1 double-balloon and 1 single-balloon RCT), the difference between groups for both cesarean delivery and postpartum hemorrhage was small and not statistically significant (SOE: low). Evidence on other outcomes in these comparisons and for misoprostol, double-balloon catheters, and hygroscopic dilators was insufficient to draw conclusions. In head to head comparisons in the outpatient setting, the frequency of cesarean delivery was not significantly different between 2.5 mg and 5 mg dinoprostone gel, or latex and silicone single-balloon catheters (1 RCT each, SOE: low). Differences between prostaglandins and placebo for cervical ripening were small and not significantly different for cesarean delivery (12 RCTs), shoulder dystocia (3 RCTs), or uterine infection (7 RCTs) (SOE: low). These findings did not change according to the specific prostaglandin, route of administration, study quality, or gestational age. Small, nonsignificant differences in the frequency of cesarean delivery (6 RCTs) and uterine infection (3 RCTs) were also found between dinoprostone and either membrane sweeping or expectant management (SOE: low). These findings did not change according to the specific prostaglandin or study quality. Evidence on other comparisons (e.g., single-balloon catheter vs. dinoprostone) or other outcomes was insufficient. For all comparisons, there was insufficient evidence on other important outcomes such as perinatal mortality and time from admission to vaginal birth. Limitations of the evidence include the quantity, quality, and sample sizes of trials for specific interventions, particularly rare harm outcomes. Conclusions. In women with low-risk pregnancies, the risk of cesarean delivery and fetal, neonatal, or maternal harms using either dinoprostone or single-balloon catheters was not significantly different for cervical ripening in the outpatient versus inpatient setting, and similar when compared with placebo, expectant management, or membrane sweeping in the outpatient setting. This evidence is low strength, and future studies are needed to confirm these findings.

Purpose/Background: Postoperative nausea and vomiting (PONV) is a frequent complaint in the postoperative period, which can delay discharge, result in readmission, and increase cost for patients and facilities. Inducing paralysis is common in anesthesia, as is utilizing the drugs neostigmine and sugammadex as reversal agents for non-depolarizing neuromuscular blockers. Many studies are available that compare these two drugs to determine if neostigmine increases the risk of PONV over sugammadex. Sugammadex has a more favorable pharmacologic profile and may improve patient outcomes by reducing PONV. Methods: This review included screening a total of 39 studies and peer-reviewed articles that looked at patients undergoing general anesthesia who received non-depolarizing neuromuscular blockers requiring either neostigmine or sugammadex for reversal, along with their respective PONV rates. 8 articles were included, while 31 articles were removed based on our exclusion criteria. These were published between 2014 and 2020 exclusively. The key words used were “neostigmine”, “sugammadex”, “PONV”, along with combinations “paralytic reversal agents and PONV”. This search was performed on the scholarly database MEDLINE. The data items were PONV rates in neostigmine group, PONV rates in sugammadex group, incidence of postoperative analgesic consumption in neostigmine group, and incidence of postoperative analgesic consumption in sugammadex group. Results: Despite numerical differences being noted in the incidence of PONV with sugammadex over reversal with neostigmine, there did not appear to be any statistically significant data in the multiple peer-reviewed trials included in our review, for not one of the 8 studies concluded that there was a higher incidence of PONV in one drug or the other of an y clinical relevance. Although the side-effect profile tended to be better in the sugammadex group than neostigmine in areas other than PONV, there was not sufficient evidence to conclude that one drug was superior to the other in causing a direct reduction of PONV. Implications for Nursing Practice: There were variable but slight differences noted between both drug groups in PONV rates, but it remained that none of the studies determined it was statically significant or clinically conclusive. This review did, however, note other advantages to sugammadex over neostigmine, including its pharmacologic profile of more efficiently reversing non-depolarizing neuromuscular blocking drugs and its more favorable pharmacokinetics. This lack of statistically significant evidence found within these studies consequentially does not support pharmacologic decision-making of one drug in favor of the other for reducing PONV; therefore, PONV alone is not a sufficient rationale for a provider to justify using one reversal over another at the current time until further research proves otherwise.

1.1 Macroeconomic summary Economic recovery has consistently outperformed the technical staff’s expectations following a steep decline in activity in the second quarter of 2020. At the same time, total and core inflation rates have fallen and remain at low levels, suggesting that a significant element of the reactivation of Colombia’s economy has been related to recovery in potential GDP. This would support the technical staff’s diagnosis of weak aggregate demand and ample excess capacity. The most recently available data on 2020 growth suggests a contraction in economic activity of 6.8%, lower than estimates from January’s Monetary Policy Report (-7.2%). High-frequency indicators suggest that economic performance was significantly more dynamic than expected in January, despite mobility restrictions and quarantine measures. This has also come amid declines in total and core inflation, the latter of which was below January projections if controlling for certain relative price changes. This suggests that the unexpected strength of recent growth contains elements of demand, and that excess capacity, while significant, could be lower than previously estimated. Nevertheless, uncertainty over the measurement of excess capacity continues to be unusually high and marked both by variations in the way different economic sectors and spending components have been affected by the pandemic, and by uneven price behavior. The size of excess capacity, and in particular the evolution of the pandemic in forthcoming quarters, constitute substantial risks to the macroeconomic forecast presented in this report. Despite the unexpected strength of the recovery, the technical staff continues to project ample excess capacity that is expected to remain on the forecast horizon, alongside core inflation that will likely remain below the target. Domestic demand remains below 2019 levels amid unusually significant uncertainty over the size of excess capacity in the economy. High national unemployment (14.6% for February 2021) reflects a loose labor market, while observed total and core inflation continue to be below 2%. Inflationary pressures from the exchange rate are expected to continue to be low, with relatively little pass-through on inflation. This would be compatible with a negative output gap. Excess productive capacity and the expectation of core inflation below the 3% target on the forecast horizon provide a basis for an expansive monetary policy posture. The technical staff’s assessment of certain shocks and their expected effects on the economy, as well as the presence of several sources of uncertainty and related assumptions about their potential macroeconomic impacts, remain a feature of this report. The coronavirus pandemic, in particular, continues to affect the public health environment, and the reopening of Colombia’s economy remains incomplete. The technical staff’s assessment is that the COVID-19 shock has affected both aggregate demand and supply, but that the impact on demand has been deeper and more persistent. Given this persistence, the central forecast accounts for a gradual tightening of the output gap in the absence of new waves of contagion, and as vaccination campaigns progress. The central forecast continues to include an expected increase of total and core inflation rates in the second quarter of 2021, alongside the lapse of the temporary price relief measures put in place in 2020. Additional COVID-19 outbreaks (of uncertain duration and intensity) represent a significant risk factor that could affect these projections. Additionally, the forecast continues to include an upward trend in sovereign risk premiums, reflected by higher levels of public debt that in the wake of the pandemic are likely to persist on the forecast horizon, even in the context of a fiscal adjustment. At the same time, the projection accounts for the shortterm effects on private domestic demand from a fiscal adjustment along the lines of the one currently being proposed by the national government. This would be compatible with a gradual recovery of private domestic demand in 2022. The size and characteristics of the fiscal adjustment that is ultimately implemented, as well as the corresponding market response, represent another source of forecast uncertainty. Newly available information offers evidence of the potential for significant changes to the macroeconomic scenario, though without altering the general diagnosis described above. The most recent data on inflation, growth, fiscal policy, and international financial conditions suggests a more dynamic economy than previously expected. However, a third wave of the pandemic has delayed the re-opening of Colombia’s economy and brought with it a deceleration in economic activity. Detailed descriptions of these considerations and subsequent changes to the macroeconomic forecast are presented below. The expected annual decline in GDP (-0.3%) in the first quarter of 2021 appears to have been less pronounced than projected in January (-4.8%). Partial closures in January to address a second wave of COVID-19 appear to have had a less significant negative impact on the economy than previously estimated. This is reflected in figures related to mobility, energy demand, industry and retail sales, foreign trade, commercial transactions from selected banks, and the national statistics agency’s (DANE) economic tracking indicator (ISE). Output is now expected to have declined annually in the first quarter by 0.3%. Private consumption likely continued to recover, registering levels somewhat above those from the previous year, while public consumption likely increased significantly. While a recovery in investment in both housing and in other buildings and structures is expected, overall investment levels in this case likely continued to be low, and gross fixed capital formation is expected to continue to show significant annual declines. Imports likely recovered to again outpace exports, though both are expected to register significant annual declines. Economic activity that outpaced projections, an increase in oil prices and other export products, and an expected increase in public spending this year account for the upward revision to the 2021 growth forecast (from 4.6% with a range between 2% and 6% in January, to 6.0% with a range between 3% and 7% in April). As a result, the output gap is expected to be smaller and to tighten more rapidly than projected in the previous report, though it is still expected to remain in negative territory on the forecast horizon. Wide forecast intervals reflect the fact that the future evolution of the COVID-19 pandemic remains a significant source of uncertainty on these projections. The delay in the recovery of economic activity as a result of the resurgence of COVID-19 in the first quarter appears to have been less significant than projected in the January report. The central forecast scenario expects this improved performance to continue in 2021 alongside increased consumer and business confidence. Low real interest rates and an active credit supply would also support this dynamic, and the overall conditions would be expected to spur a recovery in consumption and investment. Increased growth in public spending and public works based on the national government’s spending plan (Plan Financiero del Gobierno) are other factors to consider. Additionally, an expected recovery in global demand and higher projected prices for oil and coffee would further contribute to improved external revenues and would favor investment, in particular in the oil sector. Given the above, the technical staff’s 2021 growth forecast has been revised upward from 4.6% in January (range from 2% to 6%) to 6.0% in April (range from 3% to 7%). These projections account for the potential for the third wave of COVID-19 to have a larger and more persistent effect on the economy than the previous wave, while also supposing that there will not be any additional significant waves of the pandemic and that mobility restrictions will be relaxed as a result. Economic growth in 2022 is expected to be 3%, with a range between 1% and 5%. This figure would be lower than projected in the January report (3.6% with a range between 2% and 6%), due to a higher base of comparison given the upward revision to expected GDP in 2021. This forecast also takes into account the likely effects on private demand of a fiscal adjustment of the size currently being proposed by the national government, and which would come into effect in 2022. Excess in productive capacity is now expected to be lower than estimated in January but continues to be significant and affected by high levels of uncertainty, as reflected in the wide forecast intervals. The possibility of new waves of the virus (of uncertain intensity and duration) represents a significant downward risk to projected GDP growth, and is signaled by the lower limits of the ranges provided in this report. Inflation (1.51%) and inflation excluding food and regulated items (0.94%) declined in March compared to December, continuing below the 3% target. The decline in inflation in this period was below projections, explained in large part by unanticipated increases in the costs of certain foods (3.92%) and regulated items (1.52%). An increase in international food and shipping prices, increased foreign demand for beef, and specific upward pressures on perishable food supplies appear to explain a lower-than-expected deceleration in the consumer price index (CPI) for foods. An unexpected increase in regulated items prices came amid unanticipated increases in international fuel prices, on some utilities rates, and for regulated education prices. The decline in annual inflation excluding food and regulated items between December and March was in line with projections from January, though this included downward pressure from a significant reduction in telecommunications rates due to the imminent entry of a new operator. When controlling for the effects of this relative price change, inflation excluding food and regulated items exceeds levels forecast in the previous report. Within this indicator of core inflation, the CPI for goods (1.05%) accelerated due to a reversion of the effects of the VAT-free day in November, which was largely accounted for in February, and possibly by the transmission of a recent depreciation of the peso on domestic prices for certain items (electric and household appliances). For their part, services prices decelerated and showed the lowest rate of annual growth (0.89%) among the large consumer baskets in the CPI. Within the services basket, the annual change in rental prices continued to decline, while those services that continue to experience the most significant restrictions on returning to normal operations (tourism, cinemas, nightlife, etc.) continued to register significant price declines. As previously mentioned, telephone rates also fell significantly due to increased competition in the market. Total inflation is expected to continue to be affected by ample excesses in productive capacity for the remainder of 2021 and 2022, though less so than projected in January. As a result, convergence to the inflation target is now expected to be somewhat faster than estimated in the previous report, assuming the absence of significant additional outbreaks of COVID-19. The technical staff’s year-end inflation projections for 2021 and 2022 have increased, suggesting figures around 3% due largely to variation in food and regulated items prices. The projection for inflation excluding food and regulated items also increased, but remains below 3%. Price relief measures on indirect taxes implemented in 2020 are expected to lapse in the second quarter of 2021, generating a one-off effect on prices and temporarily affecting inflation excluding food and regulated items. However, indexation to low levels of past inflation, weak demand, and ample excess productive capacity are expected to keep core inflation below the target, near 2.3% at the end of 2021 (previously 2.1%). The reversion in 2021 of the effects of some price relief measures on utility rates from 2020 should lead to an increase in the CPI for regulated items in the second half of this year. Annual price changes are now expected to be higher than estimated in the January report due to an increased expected path for fuel prices and unanticipated increases in regulated education prices. The projection for the CPI for foods has increased compared to the previous report, taking into account certain factors that were not anticipated in January (a less favorable agricultural cycle, increased pressure from international prices, and transport costs). Given the above, year-end annual inflation for 2021 and 2022 is now expected to be 3% and 2.8%, respectively, which would be above projections from January (2.3% and 2,7%). For its part, expected inflation based on analyst surveys suggests year-end inflation in 2021 and 2022 of 2.8% and 3.1%, respectively. There remains significant uncertainty surrounding the inflation forecasts included in this report due to several factors: 1) the evolution of the pandemic; 2) the difficulty in evaluating the size and persistence of excess productive capacity; 3) the timing and manner in which price relief measures will lapse; and 4) the future behavior of food prices. Projected 2021 growth in foreign demand (4.4% to 5.2%) and the supposed average oil price (USD 53 to USD 61 per Brent benchmark barrel) were both revised upward. An increase in long-term international interest rates has been reflected in a depreciation of the peso and could result in relatively tighter external financial conditions for emerging market economies, including Colombia. Average growth among Colombia’s trade partners was greater than expected in the fourth quarter of 2020. This, together with a sizable fiscal stimulus approved in the United States and the onset of a massive global vaccination campaign, largely explains the projected increase in foreign demand growth in 2021. The resilience of the goods market in the face of global crisis and an expected normalization in international trade are additional factors. These considerations and the expected continuation of a gradual reduction of mobility restrictions abroad suggest that Colombia’s trade partners could grow on average by 5.2% in 2021 and around 3.4% in 2022. The improved prospects for global economic growth have led to an increase in current and expected oil prices. Production interruptions due to a heavy winter, reduced inventories, and increased supply restrictions instituted by producing countries have also contributed to the increase. Meanwhile, market forecasts and recent Federal Reserve pronouncements suggest that the benchmark interest rate in the U.S. will remain stable for the next two years. Nevertheless, a significant increase in public spending in the country has fostered expectations for greater growth and inflation, as well as increased uncertainty over the moment in which a normalization of monetary policy might begin. This has been reflected in an increase in long-term interest rates. In this context, emerging market economies in the region, including Colombia, have registered increases in sovereign risk premiums and long-term domestic interest rates, and a depreciation of local currencies against the dollar. Recent outbreaks of COVID-19 in several of these economies; limits on vaccine supply and the slow pace of immunization campaigns in some countries; a significant increase in public debt; and tensions between the United States and China, among other factors, all add to a high level of uncertainty surrounding interest rate spreads, external financing conditions, and the future performance of risk premiums. The impact that this environment could have on the exchange rate and on domestic financing conditions represent risks to the macroeconomic and monetary policy forecasts. Domestic financial conditions continue to favor recovery in economic activity. The transmission of reductions to the policy interest rate on credit rates has been significant. The banking portfolio continues to recover amid circumstances that have affected both the supply and demand for loans, and in which some credit risks have materialized. Preferential and ordinary commercial interest rates have fallen to a similar degree as the benchmark interest rate. As is generally the case, this transmission has come at a slower pace for consumer credit rates, and has been further delayed in the case of mortgage rates. Commercial credit levels stabilized above pre-pandemic levels in March, following an increase resulting from significant liquidity requirements for businesses in the second quarter of 2020. The consumer credit portfolio continued to recover and has now surpassed February 2020 levels, though overall growth in the portfolio remains low. At the same time, portfolio projections and default indicators have increased, and credit establishment earnings have come down. Despite this, credit disbursements continue to recover and solvency indicators remain well above regulatory minimums. 1.2 Monetary policy decision In its meetings in March and April the BDBR left the benchmark interest rate unchanged at 1.75%.

From this edition, the Financial Stability Report will have fewer pages with some changes in its structure. The purpose of this change is to present the most relevant facts of the financial system and their implications on the financial stability. This allows displaying the analysis more concisely and clearly, as it will focus on describing the evolution of the variables that have the greatest impact on the performance of the financial system, for estimating then the effect of a possible materialization of these risks on the financial health of the institutions. The changing dynamics of the risks faced by the financial system implies that the content of the Report adopts this new structure; therefore, some analyses and series that were regularly included will not necessarily be in each issue. However, the statistical annex that accompanies the publication of the Report will continue to present the series that were traditionally included, regardless of whether or not they are part of the content of the Report. In this way we expect to contribute in a more comprehensive way to the study and analysis of the stability of the Colombian financial system. Executive Summary During the first half of 2015, the main advanced economies showed a slow recovery on their growth, while emerging economies continued with their slowdown trend. Domestic demand in the United States allowed for stabilization on its average growth for the first half of the year, while other developed economies such as the United Kingdom, the euro zone, and Japan showed a more gradual recovery. On the other hand, the Chinese economy exhibited the lowest growth rate in five years, which has resulted in lower global dynamism. This has led to a fall in prices of the main export goods of some Latin American economies, especially oil, whose price has also responded to a larger global supply. The decrease in the terms of trade of the Latin American economies has had an impact on national income, domestic demand, and growth. This scenario has been reflected in increases in sovereign risk spreads, devaluations of stock indices, and depreciation of the exchange rates of most countries in the region. For Colombia, the fall in oil prices has also led to a decline in the terms of trade, resulting in pressure on the dynamics of national income. Additionally, the lower demand for exports helped to widen the current account deficit. This affected the prospects and economic growth of the country during the first half of 2015. This economic context could have an impact on the payment capacity of debtors and on the valuation of investments, affecting the soundness of the financial system. However, the results of the analysis featured in this edition of the Report show that, facing an adverse scenario, the vulnerability of the financial system in terms of solvency and liquidity is low. The analysis of the current situation of credit institutions (CI) shows that growth of the gross loan portfolio remained relatively stable, as well as the loan portfolio quality indicators, except for microcredit, which showed a decrease in these indicators. Regarding liabilities, traditional sources of funding have lost market share versus non-traditional ones (bonds, money market operations and in the interbank market), but still represent more than 70%. Moreover, the solvency indicator remained relatively stable. As for non-banking financial institutions (NBFI), the slowdown observed during the first six months of 2015 in the real annual growth of the assets total, both in the proprietary and third party position, stands out. The analysis of the main debtors of the financial system shows that indebtedness of the private corporate sector has increased in the last year, mostly driven by an increase in the debt balance with domestic and foreign financial institutions. However, the increase in this latter source of funding has been influenced by the depreciation of the Colombian peso vis-à-vis the US dollar since mid-2014. The financial indicators reflected a favorable behavior with respect to the historical average, except for the profitability indicators; although they were below the average, they have shown improvement in the last year. By economic sector, it is noted that the firms focused on farming, mining and transportation activities recorded the highest levels of risk perception by credit institutions, and the largest increases in default levels with respect to those observed in December 2014. Meanwhile, households have shown an increase in the financial burden, mainly due to growth in the consumer loan portfolio, in which the modalities of credit card, payroll deductible loan, revolving and vehicle loan are those that have reported greater increases in risk indicators. On the side of investments that could be affected by the devaluation in the portfolio of credit institutions and non-banking financial institutions (NBFI), the largest share of public debt securities, variable-yield securities and domestic private debt securities is highlighted. The value of these portfolios fell between February and August 2015, driven by the devaluation in the market of these investments throughout the year. Furthermore, the analysis of the liquidity risk indicator (LRI) shows that all intermediaries showed adequate levels and exhibit a stable behavior. Likewise, the fragility analysis of the financial system associated with the increase in the use of non-traditional funding sources does not evidence a greater exposure to liquidity risk. Stress tests assess the impact of the possible joint materialization of credit and market risks, and reveal that neither the aggregate solvency indicator, nor the liquidity risk indicator (LRI) of the system would be below the established legal limits. The entities that result more individually affected have a low share in the total assets of the credit institutions; therefore, a risk to the financial system as a whole is not observed. José Darío Uribe Governor