This study was an unobtrusive observational analysis of 333 older and younger bus passengers in Guadalajara, Mexico. A set of data were collected for each observed passenger, as well as more general observations related to driver behaviour, bus design and bus service characteristics. There were significant differences between older and younger passengers in terms of boarding and alighting times...

The current tendency is to provide post-approval evidence from separate, often larger and less well controlled trials. Typical examples of these are pragmatic trials (randomisation, little/no control), purely prospective observational trials (no randomisation, no control) and use of historic controls. #3 New study design: Mixed RCT (cont.) In a Mixed RCT patients would be selected and randomise...

The propensity score is defined as a subject's probability of treatment selection, conditional on observed baseline covariates. Weighting subjects by the inverse probability of treatment received creates a synthetic sample in which treatment assignment is independent of measured baseline covariates. Inverse probability of treatment weighting (IPTW) using the propensity score allows one to obtai...

The propensity score is defined as the probability of each individual study subject being assigned to a group of interest for comparison purposes. Propensity score adjustment is a method of ensuring an even distribution of confounders between groups, thereby increasing between group comparability. Propensity score analysis is therefore an increasingly applied statistical method in observational...

We tested the effects of an observational intervention (Greer & Singer-Dudek, 2008) on establishing children's books as conditioned reinforcers using a delayed multiple baseline design. Three preschool students with mild language and developmental delays served as the participants. Prior to the intervention, books did not function as reinforcers for any of the participants. The observational in...

Suppose we are interested in estimating the average causal effect from an observational study. A doubly robust estimator, which is a hybrid of the outcome regression and propensity score weighting, is more robust than estimators obtained by either of them in the sense that, if at least one of the two models holds, the doubly robust estimator is consistent. However, a doubly robust estimator may...

Parkinson's disease has multiple determinants and is associated with a wide range of exposures that appear to modify risk in traditional observational studies, including numerous lifestyle and environmental factors. Across other fields of medicine, Mendelian randomization has emerged as a powerful method to examine whether associations between exposures and disease outcomes are causal. Here we ...

Concerns have been raised about the quality of reporting in nutritional epidemiology. Research reporting guidelines such as the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement can improve quality of reporting in observational studies. Herein, we propose recommendations for reporting nutritional epidemiology and dietary assessment research by extending the...

The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement was first published in 2007 and again in 2014. The purpose of the original STROBE was to provide guidance for authors, reviewers, and editors to improve the comprehensiveness of reporting; however, STROBE has a unique focus on observational studies. Although much of the guidance provided by the original ...

OBJECTIVES Instead of evaluating one risk factor at a time, we illustrate the utility of "field-wide meta-analyses" in considering all available data on all putative risk factors of a disease simultaneously. STUDY DESIGN AND SETTING We identified studies on putative risk factors of pterygium (surfer's eye) in PubMed, EMBASE, and Web of Science. We mapped which factors were considered, reporte...