Across the country, education reformers and their allies in both parties have revamped the way teachers are graded, abandoning methods under which nearly everyone was deemed satisfactory, even when students were falling behind.

More than half the states now require new teacher evaluation systems and, thanks to a deal announced last week in Albany, New York City will soon have one, too.

The changes, already under way in some cities and states, are intended to provide meaningful feedback and, critically, to weed out weak performers. And here are some of the early results:

In Florida, 97 percent of teachers were deemed effective or highly effective in the most recent evaluations. In Tennessee, 98 percent of teachers were judged to be “at expectations.”

In Michigan, 98 percent of teachers were rated effective or better.

Advocates of education reform concede that such rosy numbers, after many millions of dollars developing the new systems and thousands of hours of training, are worrisome.