# Interactions terms and Heckit/Tobit models in Stata

I am trying to read on how to interpret interaction effects in Heckman's selection model and come across with this article ￼On Marginal and Interaction Effects: The Case of Heckit and Two-Part Models. The authors mention that they use a stata command to calculate the effects yet to specify what they used.

Let assume the regression of interest: $$y = \alpha_0 + \alpha_1 x_1 + \alpha_2 x_2 + \alpha_i x_1*x_2 + \beta X + \epsilon$$ where $y$ is the limited dependent variable and $X$ is a set of controlling variable.

I am interested in interpreting $\alpha_i$, that is effect of the interaction term between $x_1$ and $x_2$.

Could any one please point out how to calculate, and interpret, the interaction effects in Heckit/Tobit model using Stata?

Thank you!

• Be specific about your request: Are you asking for the Stata command for Heckman/Tobit or are you asking for the marginal effects from Heckman/Tobit? – Marquis de Carabas Jul 24 '15 at 0:24
• Hi! I am asking for the Stata command for marginal effects of INTERACTIONS terms from Heckman/Tobit. I have edited my question. – Thien Jul 24 '15 at 0:45
• Does this post help? – Dimitriy V. Masterov Jul 24 '15 at 1:51
• Are $x_1$ and $x_2$ continuous or binary? – Dimitriy V. Masterov Jul 24 '15 at 6:02
• @Thien I don't know the altruism literature at all, so can't help you there. – Dimitriy V. Masterov Jul 24 '15 at 21:19