Dear Applied Statistics Community, Please join us this Wednesday (tomorrow) when Judith J. Lok, Harvard School of Public Health, Department of Biostatistics, will present " Optimal start of treatment based on time-dependent covariates". Judith provided the following abstract for her talk: Using observational data, we estimate the effects of treatment regimes that start treatment once a covariate, X, drops below a certain level, x. This type of analysis is difficult to carry out using experimental data, because the number of possible values of x may be large. In addition, we estimate the optimal value of x, which maximizes the expected value of the outcome of interest within the class of treatment regimes studied in this paper. Our identifying assumption is that there are no unmeasured confounders. We illustrate our methods using the French Hospital Database on HIV. The best moment to start Highly Active AntiRetroviral Therapy (HAART) in HIV positive patients is unknown. It may be the case that withholding HAART in the beginning is beneficial, because it postpones the time patients develop drug resistance, and hence might improve the patients' long term prognosis. However, it is unknown how long initiation of HAART can safely be postponed. The paper for the talk can be found here <http://people.fas.harvard.edu/%7Ejgrimmer/lok.pdf> The applied statistics workshop meets at 12 noon in room N 354, CGIS Knafel (1737 Cambridge Street) with a light lunch. At 1215 the presentation will begin and usually runs until 130 pm. If you have any questions, please let me know-- Cheers, Justin