Researchers often invoke strong assumptions in empirical analyses to identify significant statistical outcomes. Invoking assumptions that do not sufficiently reflect the occurrence of true phenomenon reduces the credibility of inferences. Literature suggests that the potential effects of assumptions on credibility of inferences can be mitigated by comparing and combining insights from alternative econometric models. I use this recommendation to conduct robustness checks of commonly used methods in environmental and health economics. The first chapter proposes a novel nonparametric regression model to draw credible insights from meta-analyses. Existing literature on benefit-transfer validity is examined as an application. Nonparametric regression is found to be a viable approach for drawing robust policy insights. The second chapter proposes an alternative structural and simulations based framework to understand elicitation effects in survey response data. This analysis explains the structural mechanisms in which response anomalies occur and is important for building credible insights from survey data. The last chapter uses methods in program evaluation to investigate the impacts of institutional child deliveries on long-term maternal health in the context of developing countries. The outcomes of this analysis indicate that institutional deliveries positively affect maternal health in lower socio-economic states. Based on the findings of my three chapters, I recommend that researchers should combine insights from alternative models to mitigate the scope of specification bias in empirical outcomes and inform policy about the potential uncertainty that arises in uncovering the truth using statistical methods. / Ph. D.

faustino.perez@unizar.es / Objective: To assess the effects of vitamin D supplementation during pregnancy on obstetric outcomes and birth variables. Design: Systematic review and meta-analysis of randomized controlled trials (RCTs). Setting: Not applicable. Patient(s): Pregnant women and neonates. Intervention(s): PubMed and 5 other research databases were searched through March 2014 for RCTs evaluating vitamin D supplementation calcium/vitamins/ferrous sulfate vs. a control (placebo or active) during pregnancy. Main Outcome Measure(s): Measures were: circulating 25-hydroxyvitamin D [25(OH)D] levels, preeclampsia, gestational diabetes mellitus (GDM), small for gestational age (SGA), low birth weight, preterm birth, birth weight, birth length, cesarean section. Mantel-Haenszel fixed-effects models were used, owing to expected scarcity of outcomes. Effects were reported as relative risks and their 95% confidence intervals (CIs). Result(s): Thirteen RCTs (n ¼ 2,299) were selected. Circulating 25(OH)D levels were significantly higher at term, compared with the control group (mean difference: 66.5 nmol/L, 95% CI 66.2–66.7). Birth weight and birth length were significantly greater for neonates in the vitamin D group; mean difference: 107.6 g (95% CI 59.9–155.3 g) and 0.3 cm (95% CI 0.10–0.41 cm), respectively. Incidence of preeclampsia, GDM, SGA, low birth weight, preterm birth, and cesarean section were not influenced by vitamin D supplementation. Across RCTs, the doses and types of vitamin D supplements, gestational age at first administration, and outcomes were heterogeneous. Conclusion(s): Vitamin D supplementation during pregnancy was associated with increased circulating 25(OH)D levels, birth weight, and birth length, and was not associated with other maternal and neonatal outcomes. Larger, better-designed RCTs evaluating clinically relevant outcomes are necessary to reach a definitive conclusion. (Fertil Steril 2015;-:-–-. 2015 by American Society for Reproductive Medicine.) / Revisión por pares

Purpose: Adaptive servoventilation (ASV) has been reported to show improvement in patients with sleep-disordered breathing (SDB) and heart failure (HF); however, its role as a second-line or adjunctive treatment is not clear. We conducted a systematic review and meta-analysis of new existing data including cardiac mechanistic factor, geometry, and cardiac biomarkers. Methods: We systematically searched for randomized controlled trials (RCTs) and cohort studies that assessed the efficacy or effectiveness of ASV compared to conventional treatments for SDB and HF in five research databases from their inception to November 2018. Random-effects meta-analyses using the inverse variance method and stratified by study design were performed. Results: We included 15 RCTs (n = 859) and 5 cohorts (n = 162) that met our inclusion criteria. ASV significantly improved left ventricular ejection fraction (LVEF) in cohorts (MD 6.96%, 95% CI 2.58, 11.34, p = 0.002), but not in RCTs. Also, the ASV group had significantly lower apnea-hypopnea index (AHI) in both cohorts (MD − 26.02, 95% CI − 36.94, − 15.10, p < 0.00001) and RCTs (MD − 21.83, 95% CI − 28.17, − 15.49, p < 0.00001). ASV did not significantly decrease the E/e′ ratio in RCTs or in cohorts. Finally, ASV significantly decreased brain natriuretic peptide (BNP) in the cohorts (SMD − 121.99, CI 95% − 186.47, − 57.51, p = 0.0002) but not in RCTs. ASV did not have a significant effect on systolic blood pressure, diastolic blood pressure, and cardiac diameters. Conclusions: ASV therapy is associated with improvements of AHI in comparison to alternative treatments in patients with SDB and HF. ASV did not improve LVEF or E/e′ ratios in randomized trials; other intermediate outcomes did not improve significantly. / Revisión por pares

Background: Associations between dietary fats and mortality are unclear. Methods: We evaluated the relationship between quartiles of total fat, mono-unsaturated (MUFA), polyunsaturated (PUFA) and saturated fatty acid (SFA) consumption, and all-cause, coronary heart disease (CHD), stroke, and type 2 diabetes (T2D)-associated mortality in 24,144 participants from the National Health and Nutrition Examination Surveys (NHANES) 1999–2010. We added our results to a meta-analysis based on searches until November 2018. Results: In fully adjusted Cox-proportional hazard models in our prospective study, there was an inverse association between total fat (HR: 0.90, 95% confidence interval 0.82, 0.99, Q4 vs Q1) and PUFA (0.81, 0.78–0.84) consumption and all-cause mortality, whereas SFA were associated with the increased mortality (1.08, 1.04–1.11). In the meta-analysis of 29 prospective cohorts (n = 1,148,117) we found a significant inverse association between total fat (0.89, 0.82–0.97), MUFA (0.93, 0.87–0.99) and PUFA (0.86, 0.80–0.93) consumption and all-cause mortality. No association was observed between total fat and CVD (0.92, 0.79–1.08) or CHD mortality (1.03 0.99–1.09). A significant association between SFA intake and CHD mortality (1.10, 1.01–1.20) was observed. Neither MUFA nor PUFA were associated with CVD or CHD mortality. Inverse associations were observed between MUFA (0.80, 0.67–0.96) and PUFA (0.84, 0.80–0.90) intakes and stroke mortality. Conclusions: We showed differential associations of total fat, MUFA and PUFA with all-cause mortality, but not CVD or CHD mortalities. SFA was associated with higher all-cause mortality in NHANES and with CHD mortality in our meta-analysis. The type of fat intake appears to be associated with important health outcomes. / European Society of Cardiology / Revisión por pares

Chronic pain is common and frequently interferes with people’s regular functioning and reduces quality of life. Though pharmacological approaches are used most frequently to treat pain-related issues, the side effects of these medications often lead to other problems. Group therapy has been used and studied for decades in treating pain though it’s general efficacy for addressing pain is not clear. Objectives: to determine group therapy’s efficacy for patients with pain-related issues and whether the effects are moderated by study, patient, leader, or group characteristics. Method: potential articles were selected from searches completed in major databases based on a set of inclusion criteria. A random effects meta-analysis was conducted, and potential moderators were analyzed. Results: we analyzed 57 studies representing 8,933 patients receiving group therapy for pain which produced a significant, small effect (g = 0.28) for reducing pain intensity. Various secondary outcomes such as pain frequency, interference with activities of daily living, physical functioning, catastrophizing, self-efficacy, anxiety, depression, and quality of life were also found to improve significantly. Four significant moderating variables were found to include pain measure used, gender composition, number of sessions, and presence of pain diagnosis. Discussion: results are discussed and compared to those of past meta-analyses regarding both chronic pain and group therapy. Implications for practice and research are provided.

In this article, a meta-analysis was conducted using correspondence tests from 2004 and later, researching gender discrimination in the labour markets hiring process. A total of 19 correspondence tests were found from 12 different countries across the world. Comparisons of call-back rates for job applications between male and female applicants were made. I created a call-back ratio, dividing the female applicants’ call-back rate by the male applicants’ call-back rate for each study and regressed on two different variables, “equality score” and “work incentives rating”, meant to measure gender equality of countries. My hypothesis is that females are still discriminated against in the world’s labour markets. Statistical discrimination is my main theory of why discrimination of female applicants would occur in the labour market. The method of meta-analysis is useful for observing overall trends and drawing broad conclusions regarding a subject. The equality score is significantly correlated with higher call-back rates for both genders, bot it is not correlated with the call-back ratio, and therefore, does not seem to be correlated with gender discrimination. Providing more work incentives are correlated with lower call-back rates for both genders, but these findings are not significant at any level. The call-back ratio is unaffected by the work incentives rating, showing no correlation with discrimination. The main findings show no discrimination of female applicants, but rather points to discrimination of male applicants. This could be to a perceived image of men being more threatening.

The association between economic freedom and economic growth has been largely explored by researchers and the overall ndings indicate a signi cant and positive relationship. The empirical literature, however, is subject to suer from bias. In this paper we collect 16,070 estimates from 69 studies and using recently developed meta-analytic techniques investigate the eect of publication and speci cation biases on the reported results. While our baseline analysis re- ports some evidence for publication bias, but not very strong and robust, and con rms the speci cation bias reported by previous reviews, we also nd that these results are aected by the inclusion of three in uential outliers in the data set. Once we trim these studies, there is no evidence of speci cation bias anymore and we nd evidence of a robust and strong publication bias. Further, after controlling for the bias, we nd that the true eect of economic freedom on growth is substantially smaller than the eect reported by the empirical literature. JEL Classi cation O43; P10; P12; C52 Keywords 'economic freedom', 'economic growth', 'publi- cation bias', 'speci cation bias', 'meta-analysis' Title Economic freedom and economic growth: A Meta-Analysis

Treatment of acute Achilles tendon ruptures has long been controversial. Several treatment options exist for patient with variable harms and benefits to each. Recognizing that decision of treatment option is preference-sensitive, this thesis focused on updating the current literature on Achilles tendon rupture management to facilitate the creation of a patient decision aid. A network meta-analysis of all treatment options for acute Achilles tendon ruptures was performed. Results demonstrated that minimally invasive surgery options were associated with lower complications and lower complications requiring surgery. Return to sport was similar amongst all treatment groups. With guidance from the Ottawa Decision Support Framework and the International Patient Decision Aid Standards, a three-tiered protocol for development, alpha testing and field-testing a novel patient decision aid is outlined next. The patient decision aid will be reviewed and revised iteratively by multi-disciplinary steering group. This protocol will act as a framework for further orthopaedic patient decision aid development.

<p>Sustainability and reciprocity are critical and persistent obstacles in community-engaged projects. While deeply theorized at a local level, they are rarely compared in large-scale analysis—leaving sustainability and reciprocity as assumed staple points in community literacy work but difficult in transfer since written accounts are contextually and culturally specific to a local community.  Methodology becomes an essential component to how researchers negotiate knowledge practices, the intent of their research, and their relational stake in the community contexts they work within. </p> <p><br></p> <p>In order to understand how researchers name and frame methodologies in community literacy work, I synthesize fifteen years of scholarship in <em>Community Literacy Journal</em> (<em>CLJ</em>), accounting for 128 published pieces by employing qualitative meta analysis. Three questions are central to this dissertation: 1) What methodologies allow for sustainable and reciprocal work in the varied contextual circumstances of community literacy projects? 2) What might these methodological lessons mean for the larger field of Writing Studies and in turn, for writing centers? 3) How do scholars challenge academic boundaries and grand narratives so our methodological decisions in community literacy projects are grounded in cultural humility?</p> <p><br></p> <p>As most <em>CLJ</em> publications describe small-scale projects and case studies, I uncover methodological grand narratives, or lore, that become easily unseen without persistent large-scale comparisons. On the surface, grand narratives are useful for general conception. In practice, grand narratives overgeneralize the methodologies needed for working with location-specific and culturally-unique community members. What works in the wealthy suburbs of Chicago’s Northside functions differently in the South Side of the city, but the grand narratives found in accessible scholarship blur those borders.</p> <p><br></p> <p>Through analysis, I discovered surround three dominant dilemmas that <em>CLJ</em> researchers face: 1) positionality—who we are as academics within non-academic communities; 2) approach—how academics work with communities outside of academia; and 3) representation—what academics do with that work and who takes credit. </p>

Childhood obesity is a global concern. The objectives of this meta-analytical study were to evaluate the effectiveness of school-based childhood obesity prevention programs, and to examine program components (moderators). The methods included searching databases (PubMed, Google Scholar, and the university's EBSCOhost Web service) as well as handsearching reference lists of articles published in English. Selection criteria for studies to be included in the meta-analysis were limited to studies that reported body mass index (BMI) or skinfold thickness as outcome measures and were school-based obesity prevention interventions; cross-sectional design studies were excluded. We hypothesized the meta-analysis would yield a summary effect size of magnitude which would indicate that school-based interventions have been effective in improving children's BMI or skinfold thickness values. A total of 26 114 children from 27 school-based childhood obesity prevention programs provided 54 effect sizes. A random-effects model calculated a small summary effect size of 0.039 (95% confidence interval -0.013 to 0.092). Heterogeneity among studies was observed which disappeared after pooling studies that used a randomized controlled trial design with one program moderator (physical activity or nutrition). We failed to accept our hypothesis and concluded that overall, school-based interventions have not been effective for improving body mass index or skinfold thickness to curb childhood obesity; however, randomized controlled trials that focused on physical activity or nutrition appeared to produce promising results.