When the Stakes Are High, Can We Rely on Value-Added? Exploring the Use of Value-Added Models to Inform Teacher Workforce Decisions
February 08, 2011
In this report, Dan Goldhaber of the Center for
American Progress analyzes various teacher evaluation processes nationwide and
provides recommendations for improving them, since current evaluation
systems--to the surprise of no one-- fail to effectively measure the
differences in teacher effectiveness. Value Added Measures (VAMs) can replace
subjective, binary evaluation methods that have traditionally made teacher
performance assessments exercises in futility.
Teachers become undifferentiated widgets under this binary evaluation
system, despite evidence that some teachers are more effective than
others. Goldhaber suggests that
multi-year VAM estimates would decrease the risk of misclassifications by
eliminating the statistical noise that can arise from having a strong class one
year and a weaker class the next. Using VAMs would provide more transparency to
potential classification errors because they are less subjective and can be
easily evaluated since they are statistically based. He proposes an evaluation
process that uses both observational measures and VAMs to identify
low-performing teachers, and suggests that performance evaluations follow
teachers from school-to-school and district-to-district.
However, Goldhaber notes the limits of VAMs as well. Most teachers, for
example, are in classrooms or grades not covered by state standardized
assessments, such as music, art, or first and second grades, making the use of
VAMs impossible until state policies are changed. VAMs also fail to measure secondary functions
of education, such as socialization behaviors that are taught in the classroom.
Finally, VAMs focus heavily on student test scores, and this could result in
the role of teachers being reduced to “teaching to the test.”
There is growing demand to reform teacher evaluation systems and
value-added data plays an important role.
In Ohio, Cincinnati Public Schools renegotiated contracts to establish a
more rigorous evaluation process for their teachers. Evaluation methods will
now include rigorous reviews by trained evaluators as well as measures of
student growth. Statewide policy in Ohio
also is headed down this path, as HB 21
which will require the use of value-added data in evaluating teachers (in
grades and subjects for which it’s available) and principals for
Stakes Are High, Can We Rely on Value- Added? Exploring the Use of Value-Added
Models to Inform Teacher Workforce Decisions"
Center for American Progress