This survey gives a brief overview of the literature on the difference-in-difference (DiD) estimation strategy and discusses major issues using a treatment effect perspective. In this sense, this survey gives a somewhat different view on DiD than the standard textbook discussion of the...

While attempting to avoid closure, it can be argued that two of the analytical techniques employed by Lawson (1997) strongly imply closure. First, while ostensibly directed at liberating analysis from all forms of closure, the demi-reg is shown to effectively rely on implied closure. Second,...