Every measurement and every real-world number is a little bit fuzzy, a little bit uncertain. It is an imperfect reflection of reality. A number is always impure: it is an admixture of truth, error, and uncertainty.

Charles Seife, Proofiness: How You Are Being Fooled by the Numbers

Seife explains that the most well-conceived measures and carefully collected data are still imperfect. In real life situations where measurement designs are far from ideal and data collection is messy, the numbers are even more imperfect. The challenge for library assessment and research professionals is making sure our study designs and measures don’t make things any worse than they already are. To the best of our abilities we should strive to do no harm to the data.

Sharpening our skills in quantitative reasoning/numeracy will help make sure our measures aren’t exacerbating the situation. Here I’m continuing a quantitative exercise begun in my Nov. 9 post about a library return-on-investment (ROI) white paper connected with the LibValue project. In the post I explained that the ROI formula substantially exaggerated library benefits, a quantitative side-effect I suspect the researchers weren’t aware of.

A caveat before proceeding: Quantitative reasoning is not for people expecting quick and simple takeaways. Or those seeking confirmation of their pre-conceived notions. Quantitative reasoning is about thoroughness. It involves systematic thinking and lots of it! (That’s why this post is so long.) [Read more]