Hi all, I would appreciate your advice how to model the survival model for the following data, especially if it can be modeled in one model or if I should (have to) break it up (i.e. assume that some events are independent of each other, etc.). Data is on an experimental stock market simulation. Dependent variable is the hazard of transition from either holding the stock to closing the position (-1) or from not holding the stock to opening a position in that stock (1) in the variable CHNG. Main variables of interest are the regressors IV1 and IV2 (which are covariates, not factors). BUY and SELL indicate the number of stocks of type STOCK that were purchased/sold in ROUND. Accordingly, NBT and NET record the number of STOCK held at the beginning and the end of period ROUND, respectively. HP is a 0/1 dummy indicating whether or not shares of STOCK were held by an investor in any given period. And these are the issues I see in the data: 1. Over time, the stock may be held several times. This suggests a conditional hazard. TIMESHELD measures the number of times a stock has been held (meaning that the stock position must have been closed inbetween). Alternatively, it could measure the number of prior transactions in the stock (all kinds). This I intend to model with strata. 2. I also have repeated measures for individuals. As some investor may be more of a trader than others, I want to model this with a random effect (frailty). 3. Different stocks may have a different risk of being traded. This I would model with another frailty term (or would I rather model it differently?). 4. In case that an investor holds a stock, there are competing risks between increasing or decreasing the position. 5. There are also competing risks, so to speak, between the different stocks. That is, when an investor makes a buy or sell decision, s/he decides between all available stocks. One stocks competes with all other stocks to be purchased. When selling a stock though, one stock only competes with the other different stocks in the portfolio to be sold, of course. I have no idea how to model 4. and 5. though and if this is possible. I would also appreciate your feedback on the suggested way of modeling 1., 2., and 3. Apologies for the lengthy description and thanks much for your support, Daniel ID ROUND STOCK BUY SELL NBT NET IV1 IV2 HP CHNG TIMESHELD 1 1 A 0 0 0 0 3 4 0 0 0 1 2 A 10 0 0 10 3 5 1 1 1 1 3 A 0 0 10 10 5 4 1 0 1 1 4 A 0 10 10 0 2 1 1 -1 1 1 5 A 0 0 0 0 3 4 0 0 1 1 1 A 20 0 0 20 2 5 1 1 2 1 2 A 0 0 20 20 4 5 1 0 2 1 3 A 0 0 20 20 2 3 1 0 2 1 4 A 0 0 20 20 5 3 1 0 2 1 5 A 0 20 20 0 4 5 1 -1 2 2 1 B 15 0 0 15 1 2 1 1 1 2 2 B 0 0 15 15 1 2 1 0 1 2 3 B 0 0 15 15 2 2 1 0 1 2 4 B 0 15 15 0 5 1 1 -1 1 2 5 B 0 0 0 0 4 4 0 0 1 2 1 B 5 0 0 5 3 4 1 1 2 2 2 B 0 0 5 5 5 2 1 0 2 2 3 B 0 5 5 0 4 2 1 -1 2 2 4 B 0 0 0 0 4 1 0 0 2 2 5 B 0 0 0 0 4 1 0 0 2 PhD Program Strategy Dept. of Management and Organization Robert H. Smith School of Business University of Maryland Van Munching Hall College Park, MD 20742 www.rhsmith.umd.edu www.umd.edu mailto:dmalter at rhsmith.umd.edu mailto:daniel at umd.edu