There have been enough mistakes as New York State tries to reform education. New processes were rushed into service, rational demands from parents and teachers were ignored.

Gov. Andrew M. Cuomo hates the evaluation system because it lets teachers whose kids perform poorly on standardized tests be rated "effective." The teachers unions hate the system because they oppose any part of the evaluations being based on test scores, and because the results don't come in time or give enough info to be useful.

Parents? They're worried that teachers being judged on student results will spend too much time test-prepping the kids, and they say the test results are too uninformative.

So a new performance system was passed by the State Legislature last month. It says teacher effectiveness will be judged in two categories: student performance, and observation and other measures. To be judged highly effective, teachers must do well on both. To be judged ineffective, teachers must do poorly on both. Teachers who get mixed results in the two categories will be rated effective or developing, receiving no kudos but facing no repercussions.

The Board of Regents has until June 30 to set new rules, and school districts have until Nov. 15 to agree with unions on new plans. But officials may extend the deadlines. If more time is needed to get it right, it ought to be granted.

There are other legitimate complaints that need to be addressed. About $40 billion is spent in New York annually on K-12 education; a comparatively paltry $32 million goes to publisher Pearson Education to provide exams. Yet the state refuses to kick in another $8 million per year partly to double the number of questions available to the public post-test. And the state won't pay for exam results that analyze individual student performance in depth.

The tests should be of top quality, with meaningful results and timely assessments. The evaluation system should be trustworthy. It might take more time to craft this latest testing and evaluation plan so that it works, and more money. But better an effective plan that's a bit later and a bit more expensive than one delivered fast and cheap that results in more controversy and dysfunction.