Contents
- Index
Known Problems
The following is a list of known problems with the output, or bugs in the code that I have not yet been able to fix.
1. The deviance for the closed captures model divided by its degrees of freedom is not a valid estimate of c-hat. This problem carries over to the robust design model. I believe the problem is because these models are not in the exponential family, and this type of estimate of c-hat is only valid for models in the exponential family.
2. The deviance is not a good test of the goodness-of-fit of the model for sparse data. Sparse data may result from few releases, but even with lots of releases and a large number of encounter occasions, the data will be sparse. Sparse data result in small expected values for lots of the capture histories. To have observed a capture history, at least 1 animals must have been observed with this history. For a small expected value, the contribution to the deviance is large, i.e., (1 - Expected)^2 / Expected is large. To obtain a valid test of the goodness-of-fit of the model, and an appropriate estimate of c-hat, a parametric bootstrap procedure has been implemented in the Tests menu choice.
3. When you run several numerical estimation jobs at once, the program often aborts after you've appended one of these jobs to the Results Database. You can still retrieve the results from the remaining jobs by using the Output | Append menu item to open the MRK????Y.TMP temporary files. This problem is caused by bugs in the Visual Objects compiler having to do with the dynamic allocation of memory for multiple threads.
4. Program MARK is not particularly stable, mainly because of limits on the amount of available memory. Suggestions for improving the stability of the program are given here.