Dear Workshop Community, Our next meeting will be Wednesday September 25, where Matt Blackwell will present work on "On Model Dependence in the Estimation of Interactive Effects”. Abstract: Heterogeneous effects are ubiquitous in the social sciences and are often an important component of---and means of assessing---theoretical arguments. A common strategy to assess this heterogeneity is to include a single multiplicative interaction term between the treatment and a hypothesized effect moderator in a regression model. In this paper, we show how inferences about interactions under this approach are highly sensitive to modeling choices about how the effect modifier interacts with other covariates, an issue almost never discussed in practice. We propose an alternative strategy that uses machine learning techniques to allow for more flexible estimation of interactions. We apply this approach to two applications: the effect of direct primary adoption on third-party voting, with heterogeneity by region, and the effects of remittances on political protest as moderated by level of democracy. Where: CGIS Knafel Building, Room K354 (see this link <https://map.harvard.edu/?bld=04471&level=9> for directions). When: Wednesday, September 125th at 12 noon - 1:30 pm. As always, all are welcome! Lunch will be provided. Best, Georgie ** This week, Professor Iain Johnston will spend the first few minutes of the workshop introducing himself as Title IX Liaison for the Government department. Please arrive as close to 12 noon as possible so that we can get start on time. (Note: the Fall schedule for Gov 3009 can be viewed here <https://projects.iq.harvard.edu/applied.stats.workshop-gov3009>)