Hi,
I am using M-Surge for testing hypotheses about costs of reproduction (with 2 states: breeder-non breeder). I am trying to test for a linear or quadratic effect of age on transition and survival probabilities. I am using a file of external covariates defined as:
2
14 14
1 2 3 ...14
1 4 9 ... 196
With such a file, my results are pretty surprising: for example, the deviance of model Phi(t.from) Psi(t.from.a*x(1)) p(i) is higher than deviance of model Phi(t.from) Psi(t.from) p(i), and the number of identifiable parameters is the same?
When I use an additive effect of age, it seems OK: the model Phi(t.from) Psi(t.from+a*x(1)) p(i) has a lower deviance (and 2 more parameters) than model Phi(t.from) Psi(t.from) p(i).
So, can anyone explain me these surprising results and, if I am wrong (which is probably the case!) tell me how to code for a linear (and quadratic) effect of age with GEMACO?
Thanks a lot,
Sebastien