In our experimental design, we are assessing the effect of TMS on decision making. Our data is not normally distributed because our assesment test results in mean count data (ultimatum game). Besides, even randomized the previous test decisions are different across subjects as it is not possible to equalize in our case. I would prefer to rely on ANCOVA with pretest scores as covariate if they were normally distributed (not sure). But I decided to use a generalized linear model (GENLIN procedure in SPSS) instead, and use the binomial distribution with log link (as there is also too many zeros in the data set with a high variance) in SPSS.
My question is, can I use the pretest score as covariate, posttest as dependent and group as factors for GENLIN as we do it within the ANCOVA framework in many randomized trials in psychology?