Significant Marginal Effect Research Articles

The Effects of Gender and Age on Evaluation of Trainees and Faculty in Gastroenterology

We studied whether differences exist in evaluation scores of faculty and trainees in gastroenterology (GI) based on the gender of the evaluator or evaluatee, or the evaluator-evaluatee gender pairing. We examined evaluations of faculty and trainees (GI fellows and internal medicine residents rotating on GI services), using mixed linear models to assess effects of the four possible evaluator-evaluatee gender pairings. Potential confounding variables were adjusted for, and random effects were used to account for repeated assessments. For internal medicine (IM) residents, no difference in evaluation scores based on gender was found. Resident age was negatively associated with performance rating, while percentage correct on the in-training examination (ITE) was positively associated. For GI fellows, the interaction between evaluator and evaluatee gender was significant. Fellow age and international medical graduate (IMG) status were negatively associated with performance rating, while ITE percentage correct was positively associated. For faculty, no difference was found in evaluation scores by IM residents based on the gender of the evaluated faculty or the evaluating resident, although the interaction between the evaluator and the evaluatee gender was significant. Gender had a significant marginal effect on faculty scores by GI fellows, with female faculty receiving lower scores. The interaction between evaluator and evaluatee gender was also significant for evaluations by fellows. Faculty age was negatively associated with performance rating. Gender, age, and ITE performance are associated with evaluation scores of GI trainees and faculty at our institution. The interaction of evaluator and evaluatee gender appears to play a more critical role in evaluation scoring than the gender of the evaluatee or evaluator in isolation.

Genome-wide association analyses of esophageal squamous cell carcinoma in Chinese identify multiple susceptibility loci and gene-environment interactions

We conducted a genome-wide association study (GWAS) and a genome-wide gene-environment interaction analysis of esophageal squamous-cell carcinoma (ESCC) in 2,031 affected individuals (cases) and 2,044 controls with independent validation in 8,092 cases and 8,620 controls. We identified nine new ESCC susceptibility loci, of which seven, at chromosomes 4q23, 16q12.1, 17q21, 22q12, 3q27, 17p13 and 18p11, had a significant marginal effect (P=1.78×10(-39) to P=2.49×10(-11)) and two of which, at 2q22 and 13q33, had a significant association only in the gene-alcohol drinking interaction (gene-environment interaction P (PG×E)=4.39×10(-11) and PG×E=4.80×10(-8), respectively). Variants at the 4q23 locus, which includes the ADH cluster, each had a significant interaction with alcohol drinking in their association with ESCC risk (PG×E=2.54×10(-7) to PG×E=3.23×10(-2)). We confirmed the known association of the ALDH2 locus on 12q24 to ESCC, and a joint analysis showed that drinkers with both of the ADH1B and ALDH2 risk alleles had a fourfold increased risk for ESCC compared to drinkers without these risk alleles. Our results underscore the direct genetic contribution to ESCC risk, as well as the genetic contribution to ESCC through interaction with alcohol consumption.

Is the number of TACE treatments in HCC patients associated with improved survival? A SEER-Medicare population analysis.

210 Background: We examine treatment patterns and associated survival outcomes of TACE at all stages of Hepatocellular Carcinoma in SEER Medicare. Methods: Medicare enrollees, 65 and older, with a diagnosis of a primary HCC between 2000-07 who received treatment were followed through end of 2009 using the Surveillance, Epidemiology and End-Results Program (SEER) and linked Medicare databases, with claims from Medicare parts A and B. Using Cox proportional hazards models, we assessed the impact on mortality, of each additional TACE, systemic chemotherapy, SIRT, external beam radiation therapy, ablation and surgical resection, controlling for cancer stage, general health status, underlying liver disease (alcohol related, Hepatitis B and C, moderate/severe liver dysfunction), and demographics. We assessed overall and HCC-related mortality for all, then for TACE-only treated patients, and stratified outcomes by stage. Results: Out of 3322 treated non-transplant HCC patients, 1094 got TACE, 74% were Caucasian, 6% African American, 66% male, and 45% were at stage 1/2, 17% at stage 3 and 14% at stage 4. Most (56%) received 1, 23% 2, 11% 3 and 10% 4 or more TACEs. In the adjusted models, both overall and HCC mortality reduction were associated with treatment with up to 2 TACEs (HR=0.68, P=<0.001 and HR=0.73, P=<0.001, respectively). A third TACE, but not a fourth, provided a further decrease in overall mortality (0.46, <0.001) and HCC mortality (.45, <0.001). When stratified by stage, the second TACE had a significant marginal effect within Stage 3, and only the first TACE had benefit within Stage 4. No effects were found for TACE in early HCC. In the adjusted models, liver conditions were not associated with HCC mortality among TACE treated patients only. Conclusions: TACE provides a survival benefit for elderly HCC patients in clinical practice. However, the survival benefit may decrease beyond 3 TACE treatments and varies by stage. Additional TACE treatments may be confounded if 4+ TACE treatments are utilized mainly to treat biologically aggressive disease related to extensive tumor burden, advanced disease or recurrences. Treatment selection bias cannot be excluded and should be further explored.

The Basel II reform and the provision of finance for R & D activities in SMEs: An analysis of a sample of Italian companies

In this article, we investigate the issue of the financing of R & D investments in SMEs in Italy with respect to the changes in the banking system, which are driven by the adoption of the new version of the Basel Capital Accord. Results from an instrumental variable (IV) probit model show a significant and large marginal effect of both indicators of R & D activity and R & D intensity on the probability that firms report unsatisfied credit needs. We find that the introduction of the new rules is likely to have a moderate impact on the capital requirements of banks when considering the possibility for a bank to pool together all the companies in its portfolio. However, we obtain an increase in capital requirements when we focus on the sub-sample of firms performing product innovation. In particular, the analysis suggests that the new rules on regulatory capital requirements might have a negative impact on lending conditions for those SMEs that are relatively younger, smaller and showing positive R & D expenditures.

Distributed generation: An empirical analysis of primary motivators

What was once an industry dominated by centralized fossil-fuel power plants, the electricity industry in the United States is now evolving into a more decentralized and deregulated entity. While the future scope and scale of the industry is not yet apparent, recent trends indicate that distributed generation electricity applications may play an important role in this transformation. This paper examines which types of utilities are more likely to adopt distributed generation systems and, additionally, which factors motivate decisions of adoption and system capacity size. Results of a standard two-part model reveal that private utilities are significantly more inclined to adopt distributed generation than cooperatives and other types of public utilities. We also find evidence that interconnection standards and renewable portfolio standards effectively encourage consumer-owned distributed generation, while market forces associated with greater market competition encourage utility-owned distributed generation. Net metering programs are also found to have a significant marginal effect on distributed generation adoption and deployment.

The Basel II Reform and the Provision of Finance for R&D Activities in SMEs: An Analysis for a Sample of Italian Companies

In this article, we investigate the issue of the financing of R & D investments in SMEs in Italy with respect to the changes in the banking system, which are driven by the adoption of the new version of the Basel Capital Accord. Results from an instrumental variable (IV) probit model show a significant and large marginal effect of both indicators of R & D activity and R & D intensity on the probability that firms report unsatisfied credit needs. We find that the introduction of the new rules is likely to have a moderate impact on the capital requirements of banks when considerino the possibility for a bank to pool together all the companies in its portfolio. However, we obtain an increase in capital requirements when we focus on the sub-sample of firms performing product innovation. In particular, the analysis suggests that the new rules on regulatory capital requirements might have a negative impact on lending conditions for those SMEs that are relatively younger, smaller and showing positive R & D expenditures.

THE DEATH PENALTY MEETS SOCIAL SCIENCE: Deterrence and Jury Behavior Under New Scrutiny

▪ Abstract Social science has long played a role in examining the efficacy and fairness of the death penalty. Empirical studies of the deterrent effect of capital punishment were cited by the Supreme Court in its landmark cases in the 1970s; most notable was the 1975 Isaac Ehrlich study, which used multivariate regression analysis and purported to show a significant marginal deterrent effect over life imprisonment, but which was soon roundly criticized for methodological flaws. Decades later, new econometric studies have emerged, using panel data techniques, that report striking findings of marginal deterrence, even up to 18 lives saved per execution. Yet the cycle of debate continues, as these new studies face criticism for omitting key potential variables and for the potential distorting effect of one anomalously high-executing state (Texas). Meanwhile, other empiricists, relying mainly on survey questionnaires, have taken a fresh look at the human dynamics of death penalty trials, especially the attitudes and personal background factors that influence capital jurors.

A TIME SERIES ANALYSIS OF VIOLENT CRIME AND ITS RELATION TO PROLONGED STATES OF WARFARE: THE ISRAELI CASE*

This study examines the effect of security‐related stressors (e.g., wars and more prolonged states of belligerence) on violent crime patterns. Two alternative hypotheses are put forward: the cohesion hypothesis, which predicts a decrease in criminal violence in times of increased security‐related stress, and the legitimation‐habituation hypothesis, which predicts an increase in criminal violence in such periods. The study uses monthly data collected in Israel over 15 years. Security‐related casualties and incidents are the security‐related stressors, homicide and robbery are the measures of criminal violence, and economic and sociodemographic indicators are the control variables. The analysis uses a multiple regression model with autoregressive errors. The reported number of casualties had a significant marginal positive effect on homicide, thus supporting the legitimation‐habituation hypothesis. Such an effect could not be detected for the robberies series. Inflation increments had a strong positive effect on both series, and rates of unemployment had a significant marginal positive effect on robbery but not on homicide. The effects of the various stressors are not contemporaneous but extend to several months ahead. Some theoretical aspects of the findings and their implications for Israeli society are discussed.