Mandell Marvin B
University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
Eval Rev. 2008 Oct;32(5):415-34. doi: 10.1177/0193841X08316672. Epub 2008 May 5.
Both true experiments and regression discontinuity (RD) designs produce unbiased estimates of effects. However, true experiments are, of course, often criticized on equity grounds, whereas RD designs entail sacrifices in terms of statistical precision. In this article, a hybrid of true experiments and RD designs is considered. This hybrid entails smaller sacrifices in statistical efficiency than RD designs and also is likely to be judged as being considerably more fair than true experiments and possible even RD designs. Moreover, unlike pure RD designs, the hybrid design considered here can be employed in situations in which the variable on which assignment to treatment condition is based takes on only a discrete set of values.
真实验和回归断点（RD）设计都能产生无偏的效应估计。然而，真实验当然经常因公平性问题受到批评，而RD设计在统计精度方面会有所牺牲。在本文中，我们考虑一种真实验和RD设计的混合方法。这种混合方法在统计效率方面的牺牲比RD设计更小，而且可能会被认为比真实验甚至可能比RD设计更加公平得多。此外，与纯RD设计不同，这里考虑的混合设计可用于基于其进行处理条件分配的变量仅具有离散值集的情况。
