A colleague has data of the following general structure:
Treatment T
Year Site
1 T1 T2 T3 T4
2 T1 T2 T3 T4
(Same sites both years)
Control C
Year Site
1 C1 C2 C3 C4
2 C1 C2 C3 C4
(Same sites both years)
For each site and year, n organisms are found, and k of those respond in
a certain way. (n varies from 3--36 over the 16 site-year combinations).
We are interested in whether and how much the change in ps=k/n, the
probability of success, from year 1 to year 2 differs between the
treatment and control.
Question: Is there a way to use logistic regression here that
would account for the pairing of sites across years, and would
allow for a test of whether
[ps(control,year2)/ps(control,year1)]/[ps(treatment,year2)/ps(treatment,year1)]
is detectably greater than unity?
Thanks for any advice.
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