An interesting sendup of value added on the heels of the recent CPD/SIO VA series
A key paragraph from the article:
A thought about using value added in a different way....for each teacher that has value added scores, report the results by the percentage of students that each teacher has in each category (x% greater than 2 SD above the gain line, y% b/w 1 and 2 SD above, z% b/w 0 and 1 SD above, etc.) Then, for policy purposes, examine the corresponding percentage of students in each band who are considered to come from poverty based on subgroup guidelines. The current method of assigning a single VA score for teachers does not accurately give credit for those students for whom the measure indicates the teacher caused growth.
Much larger than this is still the issue that VA scores are still derived from one test given at one point in time. This singular, two hour window can not account for the other 900 hours of instruction that children receive, and all of the intangible value teachers add to students throughout the course of a year.
If the state and federal government are serious about measuring the value that teachers add to students, create a series of quarterly assessments for each subject, each year, and combine that score with a portfolio of student work that is rubric scored and normed against expected work outputs at each grade level.
(An article from The Atlantic that also addresses the issues around the reform movement and accountability)
Singular measures of student growth are the least statistically reliable. The solution above would be expensive. But if the bureaucrats and private corporations ever want these measures to be taken seriously, the must be a movement away from tests given at one point in a school year driving the entire accountability structure for teachers and schools.