Wednesday, September 16, 2009

The ethics of random assignment

Tyler Cowen at MR asks for information related to the ethics of random assignment.

I am going to put my comments here as not everyone who reads this blog may delve into the comments (or even, gasp, the posts) at MR.

Most of my experience with these issues is in the context of randomized evaluations of social and educational programs rather than the clinical trials that are likely to be of greater interest at NIH.

I have the following comments:

1. Ethical concerns about random assignment in the social policy world are nearly always fake. They are a nice way of saying that the person has some interest in there not being compelling evidence on the effectiveness of the treatment being evaluated.

2. It is easier to sell random assignment for demonstration programs, which by design are going to leave many people who want service without it in any event, than on-going programs. With on-going programs it is easier to sell random assignment for programs that are capacity constrained, so that services will have to be rationed in some way even in the absence of random assignment. Random assignment then just becomes a way of doing the rationing that happens to yeild an informative byproduct. This is the line that was popularized by Judy Gueron during her days running MDRC, which did many of the welfare-to-work experiments in the US in the 1980s and 1990s.

3. An argument that is not often made, but which in my experience is quite convincing even to non-classical-liberal types is that there is a competing ethical claim associated with using tax money to fund the provision of services without solid evidence of their efficacy. Just as the shareholders of a firm would rightly be upset if it undertook major investments without doing its due diligence beforehand, taxpayers should rightfully be upset when government spends money on programs without doing the (in many cases) simple, obvious and relatively inexpensive things required to determine their efficacy, or lack thereof.