Gershom, you’re right about a number of things in your“Politics of Measurement” post. Science is never free of social, economic, and cultural constraints, even if the scientific method offers, by and large, a good way to minimize those influences and approach the truth. And proving cause-and-effect relationships in politics and relations between nations is a hazardous undertaking. The influences are complex and interlocking, you don’t have a control group, and experiments can’t be repeated.
In the specific case at hand, the separation barrier, you are also correct that it is very difficult to isolate the anti-terror effect of the fence from other factors. As you note, political changes took place in parallel to the construction of the fence. And Israel also conducted an anti-terror offensive, using a variety of military measures.