Re: st: Calculating and interpreting effect size when DV is a proportion

[Jeffrey Wooldridge <jmwooldridge60@gmail.com>]

I would use the "margins" command to compute the average marginal
effects. That we you do not have to fix the explanatory variables
(continuous or binary) at any specific values. For the binary
variables, you get the change in the predicted y when the dichotomous
variable goes from zero to one. For the continous variables you get
the effect of a one-unit increase in x (provided that is a reasonable
change and the calculus approximation is sensible).

Jeff W.

On Sat, Jan 12, 2013 at 7:50 PM, Michelle Dynes
<dynes.michelle@gmail.com> wrote:
> Hello,
>
> I am conducting analyses using proportion data as my outcome. I am
> using GLM with a logit link and the binomial family to carry out the
> analyses. I would like to determine the effect size of my independent
> variables. Here are two options I have considered:
>
> Generate Odds Ratios using the -eform- command at the end of the GLM
> statement. Does this make sense to do when my outcome is not
> dichotomous?
>
> Generate Marginal effects using -mfx-, holding my continuous variables
> at their mean and dichotomous variables at 0.
>
> Which method is most appropriate with a dependent variable that is a proportion?
>
> For either method, how do I interpret (either the OR or dydx) for my
> continuous variables and for my dichotomous variables?
>
> I appreciate any insight you can provide,
>
> Michelle
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