I am trying to compute the marginal effects of an xtlogit model. I tried several methods.

First of all, in order to compute the marginal effects at the mean, I used

- mfx compute

- margins, dydx(*) at mean

which both give me -0.33

Secondly, in order to compute the average marginal effects, I used

- margeff : which gives me a -0.05

- margins, dydx(*) : which gives me -0.33

I am confused because I thought that the two commands should give me similar results. What do you think explains this difference?

In addition, I am using this to estimate the marginal effects of a difference-in-difference coefficient. Is it correct to interpret the average marginal effect as: "the probability of outcome variable=1 is on average 5% (or 33%?) lower for individuals in the treatment group" using a logit model?

Thank you very much in advance