Theory and things that can and do go wrong?

Pulled this from some economic/Investment reading and I feel it applies to more than economics… like Environment and Geology for two..

“The problem we have today in economics is that many people, and not a few economists, seem to regard economics as “pure science,” as described above by Gauri Shankar Shrestha. If you delve deep into measurement theory, you find that all too often the way in which you measure something determines the results obtained from your experimental model. How you measure the effectiveness of a drug can sometimes determine whether it gets approved – apart from whether it actually does any good. The FDA actually works rather hard at measurement theory.

And if you’re using models, as we do in economics, to determine policies

“And Now the Rest of the Story – “Theory and things that can and do go wrong?