Marginal effects with margins

[Amaya Walter]

After running a Tobit model, I want to find the marginal effects using,

margins, dydx ( XX) atmeans

But, I want to limit some parameters without taking the all at their mean.
How can I write the syntax for such command?

[Clyde Schechter]

The -at()- option of -margins- allows you to designate specific values of model variables, not just the means, to which you can restrict the values of the independent variables when calculating the marginal effects. You will get a separate marginal effects estimate for each such value you specify. Open -help margins- and scroll to the explanation of the -at(atspec)- option. Then click on atspec to see the details of how this is done.