The The Iron Law of Evaluation (Rossi, 1987) is that the expected value of any net impact assessment of any large scale social program is zero.


Why does this happen? The simple answer is that in a largely-rich, largely-free country, with many existing (if confusing) private and public supports for low-income people, it’s just as easy to screw things up than to make things better, no matter how much you spend.

Source: The Iron Law – spottedtoad