BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20260710T182840EDT-3029Zj7bUR@132.216.98.100 DTSTAMP:20260710T222840Z DESCRIPTION: \nA word of caution regarding stabilized weights when using ma rginal structural models to estimate the effect of exposure history\nDenis Talbot\, PhD\n Biostatistics Professor\, Department of Social and Preventi ve Medicine\, Laval University\nAbstract:\nMarginal structural models (MSM s) are commonly used to estimate the causal effect of a time-varying expos ure in presence of time-dependent confounding. These models have gained va st popularity over the recent years\, in part due to their ease of impleme ntation. Indeed\, the most common implementation of MSMs consists of fitti ng a weighted outcome model (e.g. a linear regression)\, where observation s are weighted according to their inverse-probability-of-treatment weights . Users must however be wary of a number of subtle issues regarding MSMs t hat might impact the validity of the inferences. In this talk\, I first in troduce MSMs and then present one such issue: the stabilization of the wei ghts. This stabilization is usually recommended to reduce variability\, bu t I provide a simple example and some simulation results where it is also observed to yield biased inferences.\nBio:\nhttps://sites.google.com/site/ denistalbotfmed1/home\n DTSTART:20150922T193000Z DTEND:20150922T203000Z LOCATION:Room 24\, Purvis Hall\, CA\, QC\, Montreal\, H3A 1A2\, 1020 avenue des Pins Ouest SUMMARY:Biostatistics Seminar URL:/channels/event/biostatistics-seminar-254824 END:VEVENT END:VCALENDAR