Monday’s story about Violet Nichols offered a glimpse into what it takes for a Virginia school system to fire a tenured teacher — and what it takes for that teacher to fight for her job.

Violet Nichols (R), a tenured teacher who was terminated by Fairfax County Public Schools with her attorney Steven Stone, talk about the attempts to fire her in Alexandria. (Linda Davidson/TWP)

Readers have both endorsed and decried the use of test scores to judge teachers. They’ve suggested that parents and students be allowed to weigh in on teachers’ job evaluations. And one person e-mailed me to endorse the installation of permanent video cameras inside classrooms.

But no one (anywhere) has figured out a perfect way to evaluate the complicated work that teachers do inside their classrooms. It’s one of the most pressing and vexing questions in American education right now.

“Virtually everyone agrees that teacher evaluation in the United States needs an overhaul,” wrote Linda Darling-Hammond, a Stanford education professor, in a paper published last month.

In the Washington region, school systems have taken wildly different approaches to the problem.

The District did away with tenure in 2009 under then-chancellor Michelle A. Rhee. Now, any teacher rated ineffective is apt to be fired, and half of teacher evaluations are based on student performance — often, test scores.

That is supposed to inject objective data into the often subjective business of judging a teacher, but it’s raised its own hard questions about fairness.

A couple months ago, my colleague Bill Turque wrote a fascinating story about a D.C. teacher who received marks during classroom observations. Her principal called her “creative” and “motivating” -- but her kids did not score high enough on springtime standardized tests. She was fired (and was snapped up immediately, in fact, by a Fairfax County school).

In Montgomery County, struggling teachers are paired with a mentor, and after a year of that extra help, a panel of the teachers’ peers — including other teachers and principals — decides whether she has improved enough to keep her job.

That process, endorsed by Montgomery’s powerful teachers’ union, has resulted in the dismissal of 245 teachers since it was instituted 2001, according to my colleauge Michael Alison Chandler. In the decade before, Chandler wrote, only a handful of teachers were dismissed in Montgomery.

In Virginia, the state recently mandated that school systems overhaul their teacher evaluations, making student performance a “significant” portion for the first time. School systems have until July 1 to comply; Fairfax County will unveil its proposal on Monday.