This lightning review covers an article in under 10min. This piece reports on data looking to find out if the National School Lunch Program is a valid measure of educational disadvantage. Most researchers use this measure to say it is, and schools get huge sums of money based on this measure...but how valid is it?

Here is the citation, and a link to the article. 

Domina, T., Pharris-Ciurej, N., Penner, A. M., Penner, E. K., Brummet, Q., Porter, S. R., & Sanabria, T. (2018). Is Free and Reduced-Price Lunch a Valid Measure of Educational Disadvantage?. Educational Researcher, 47(9), 539-555.

https://journals.sagepub.com/doi/pdf/10.3102/0013189X18797609