> In 2012-13, 68.75 percent of her students met or exceeded state standards in both English and math. She was labeled “effective” that year. In 2013-14, her students’ test results were very similar but she was rated “ineffective.”
That sure makes it sound like the measure is unstable. If it is then, at a minimum, output for a single year should not be used by itself, but only in a rolling average with other years. It seems unlikely that the effectiveness of a veteran teacher would change that much from year to year. Given that there was little change in outcomes (no big drop in test scores) the hypothesis of the measure being unstable seems more likely.
That sure makes it sound like the measure is unstable. If it is then, at a minimum, output for a single year should not be used by itself, but only in a rolling average with other years. It seems unlikely that the effectiveness of a veteran teacher would change that much from year to year. Given that there was little change in outcomes (no big drop in test scores) the hypothesis of the measure being unstable seems more likely.