Invited commentary on: Fear reduction by psychotherapies

Invited commentary on: fear reduction by psychotherapies.

Invited Commentary Invited Commentary: Effect Modification by Time-varying Covariates

Marginal structural models (MSMs) allow estimation of effect modification by baseline covariates, but they are less useful for estimating effect modification by evolving time-varying covariates. Rather, structural nested models (SNMs) were specifically designed to estimate effect modification by time-varying covariates. In their paper, Petersen et al. (Am J Epidemiol 2007;000:000–00) describe h...

Invited Commentary Invited Commentary: Positivity in Practice

Positivity, or the experimental treatment assignment assumption, requires that there be both exposed and unexposed participants at every combination of the values of the observed confounders in the population under study. Positivity is essential for inference but is often overlooked in practice by epidemiologists. This issue of the Journal includes 2 articles featuring discussions related to po...

Invited Commentary Invited Commentary: Dietary Pattern Analysis

The analytic approaches used in nutritional epidemiology for dietary pattern analyses share common characteristics with those of genetic epidemiology. In this issue of the Journal, Gorst-Rasmussen et al. (Am J Epidemiol. 2011;173(10):1097–1104) discuss one such approach. Application of methods used in genetic pattern analyses to nutritional epidemiology could prove valuable but raises important...

Invited Commentary Invited Commentary: Rescuing Robinson Crusoe

Estimating the independent effect of ‘‘place’’ on health outcomes has proven quite difficult. In this issue of the Journal, Auchincloss and Diez Roux contribute a lucid introduction to agent-based simulation models and argue that they may be a fruitful alternative to current approaches to the problem. Insofar as conceptual understanding must precede empirical investigation, this author agrees. ...