Getting lost during the national attention on the recent Chicago Teachers strike was that administrators in the Los Angeles Unified School District agreed to have student achievement be part of their job evaluation, an unprecedented arrangement.

What remains to be seen is which specific results will encompass “student achievement.” Will class grades be used? How about AP test results? What about standardized test scores? These questions are to be answered before the one-year test run of this evaluation system commences.

What’s wrong about using numbers in evaluating administrators and teachers for that matter is that a statistic will not reveal if an administrator is communicating effectively with faculty members. Likewise, test scores say nothing about how engaged and involved students are with a teacher’s lesson. This issue was at the core the Chicago teachers strike, not salary and benefits.

There are ways to evaluate administrators and teachers. However, such a practical system of observing certain behaviors requires a high level of training and can be time-consuming. Numbers are easy—people-free, in fact. Cold statistics may work when doing one’s taxes, but when teaching young people, the numbers just don’t add up.

BRIAN CROSBY is a teacher in the Glendale Unified School District and the author of "Smart Kids, Bad Schools and The $100,000 Teacher." He can be reached at brian-crosby.com.