[jrumbut]

> identify and weed out the worse teachers

By and large, everyone knows.

Data might be useful to tell you "hey that longtime great teacher approaching retirement has checked out early" or "the new hire who was struggling last semester has turned the corner" but it's no secret in a school building which teacher everyone hates and which one everyone loves.

If you woke up tomorrow and discovered you were an elementary school principal, you would have the lay of the land by week two at the latest.

The problem is not separating the flowers from the weeds, it's what will happen if you pull the weeds. Who's gonna take care of that room full of 8 year olds tomorrow? And for the next several years? If a weed shows up every day and doesn't commit any crimes, the downside of replacing them is larger than the upside.

[vondur]

Most teachers have strong union protections. It’s nearly impossible to fire one. Many districts now have a temporary period where they can be removed much easier. Once they have tenure it’s really difficult.

[hunterpayne]

Tenure for a 3rd grade teacher is crazy.

[LtWorf]

> By and large, everyone knows.

For elementary school they absolutely do not know.

In my town the most acclaimed teachers were those organising many recitals with the kids and stuff like that.

Except that 20 years later parents were saying to the strict ones that just taught the material how good they were.

So yeah everybody knows. Not immediately though!