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 Christian M. Connell posted on Tuesday, October 20, 2009 - 8:56 pm
Can the monte carlo utilities be used to estimate power for covariate effect in a DTSA model? I was trying to use the corresponding monte carlo code for example 6.20 as a guide to develop a model to estimate survival across 7 periods, but having some difficulty.

Specifically:
1) not clear exactly how to modify the population statement to set-up a given hazard model with low frequency event
2) the %sig for x on f (at least as I specified the model) jumps from 0.000 at one sample size (e.g., 225) to the next increment (e.g., 226).

Thanks for any guidance you can offer!
 Christian M. Connell posted on Wednesday, October 21, 2009 - 8:49 am
Sorry, just realized that #2 (above) should have read: he %sig for x on f (at least as I specified the model) jumps from 0.000 at one sample size (e.g., 225) to 1.000 at the next increment (e.g., 226).
 Linda K. Muthen posted on Wednesday, October 21, 2009 - 9:25 am
1. The thresholds are the parameters that control this. Higher thresholds represent more rare events.
2. Please send the two outputs and your license number to support@statmodel.com.
 Christian M. Connell posted on Wednesday, October 21, 2009 - 9:49 am
Will do --

I discovered the error that was leading to my sample size finding (had another model statement later in the code that was incorrect). However, now have an issue where the covariate effect power jumps the same way (0.000 at .3 vs. 1.000 at .31) for a given n. Will send outputs/license as indicated.

Thank you
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