cloglog logistic regression interpretation
Javier Atalah <Javier.Atalah at ...> writes:
Hi,
Could someone advise me on how to interpret the estimates from a
logistic regression using a cloglog link?
I have fitted the following model in lme4:
glm(cbind (dead, live) ~ time + factor(temp) * biomass, data=mussel,
family='binomial' (link=cloglog)) This is not actually a mixed model -- you're using glm(), not glmer(). Even if you were using glmer(), this question is not specifically related to mixed models, it's a more general, GLM-related question. Asking in a more general statistics forum such as CrossValidated (http://stats.stackexchange.com) would be more appropriate (I took a quick look there and didn't find anything exactly answering your question).
Estimate Std. Error z value Pr(>|z|) (Intercept) -4.970 0.428 -11.61 3.64E-31 time 0.015 0.001 12.15 5.81E-34 temp19 2.845 0.235 12.1 1.00E-33 biomassL -0.654 0.148 -4.42 9.73E-06 temp19:biomassL 0.484 0.194 2.49 1.27E-02
Is it correct to say, for example, the estimate of time is 0.015 Thus 1 - (EXP (-EXP (-0.015))) = 0.627
That means the probability of mortality is increasing 62.7% per unit increase of time if all other variables were held constant?
You can't quite do this. What you know is that the *log-hazard* increases by 0.015 per time unit, so the hazard (probability of mortality per unit time) is multiplied by exp(0.015) = 1.015113 \approx 1.5% per passing time unit. Good luck (this looks like a good CV question, but don't forget to read http://stats.stackexchange.com/help/how-to-ask ) Ben Bolker