Well, isn’t this nice: Employee-misconduct records will now be available to New York City public-school principals who are hiring from within the sclerotic system.

It would be even nicer to know why such a fundamental employment practice wasn’t already standard operating procedure.

“Gaps in the system,” the Department of Education tries to explain.

Gaps in somebody’s head is more like it.

But now Schools Chancellor Dennis Walcott says rap sheets will be included in personnel files where appropriate.

Sadly, it took three recent cases of school personnel abusing students — two individuals with priors — to get a new policy crafted.

To wit:

* Queens teacher Wilbert Cortez was charged last week with molesting male students at PS 174. In 2000, he was investigated at his previous school for inappropriate touching; the only action taken against him was a letter in his file.

* Teachers aide Gregory Atkins of Manhattan’s PS 87 was arrested for abusing a student. In 2006, he was investigated for giving inappropriate gifts (including a jockstrap) to a student; he received only a verbal reprimand.

(Brooklyn PS 243 teachers aide Taleek Brooks, charged this month with molesting kids and possessing child porn, apparently had no priors.)

The principals at Cortez and Atkins’ schools might have benefited from knowing more about what went on at the previous stops — and declined to hire them.

Next question: How many other pervs are scattered throughout the system?

DOE doesn’t know — yet.

Walcott promises a full review, going back to 2000, to identify school employees with past questionable incidents.

How effective that will be remains to be seen — given that there’s no reason to believe adequate records or earlier episodes even exist. (See above, Gregory Atkins.)

But the intention is to remove employees from contact with children where appropriate (and, doubtless, shuffle them off to years of fully paid indolence while administrators and union lawyers hash out the fine print).

All of this has an Alice-in-Wonderland aura about it.

The seeming indifference to reports of student predation, coupled with typically slovenly record-keeping, suggests that this could be a scandal with real legs.

For sure, the department’s notoriously obstructionist bureaucracy will have no stomach for digging out the details.

Somebody should sic a tort lawyer or two on them. That would get things moving.