Understanding the Tennessee Value-Added Assessment System (TVAAS) Dec. 2014 | Page 2

INTRODUCTION
Research shows that teaching has a greater impact on student learning than
any other in-school factor.1 Tennessee’s efforts to maximize student achievement involve an accurate and comprehensive assessment of teacher quality,
including a measurement of student academic growth.

WHAT IS TVAAS?
Until recently, teacher evaluations in Tennessee made little use of student
achievement data. Under the previous system, teachers were often labeled as
effective or ineffective based on infrequent classroom observations, making

1992
Education
Improvement Act
The Education
Improvement Act
introduced TVAAS in
1992, requiring the
state to monitor student
gains.

it very difficult to determine how much of an impact teachers made on their
students’ learning. A national study published in 2009 found that 94 to 99
percent of teachers received a positive rating on their evaluations, despite high
failure rates in student achievement.
In the late 1980s, two professors at the University of Tennessee developed
a way to measure teacher impact on student learning called the Tennessee
Value-Added Assessment System (TVAAS).2 Instead of focusing on student
achievement levels, TVAAS measures how much a student has grown from
one year to the next. TVAAS, when used alongside other evaluation tools such
as classroom observations or student surveys, can help schools and districts
to better understand the quality of teaching happening in their classrooms
and provide teachers with feedback and support tailored specifically to their
needs.3 Table 1 outlines the history of TVAAS in Tennessee:

1993-2010
TVAAS Reports

2010 First
to the Top Act

Principals and teachers
received TVAAS reports
annually, but these
reports were only
informational. There was
no standardized method
for discussing or utilizing
these results.

TVAAS data was added
to Tennessee teacher
evaluations, making up
35% of the evaluation
for teachers of statetested subjects and
25% for other teachers.

2013 Teacher
and Principal
Evaluation Policy

Table 1

Source: Measuring Student Growth in Tennessee: Understanding TVAAS

As illustrated in Table 2, state law requires that TVAAS data make up at least
35 percent of evaluation scores for teachers of state-tested subjects, such as
math and English, and 25 percent of scores for all other teachers. The rest
of the score is determined by other student achievement data and a variety
of other measures such as classroom observations and student surveys.
(In December 2014, Governor Bill Haslam announced he would seek
legislative approval of adjustments to the weighting of TVAAS data in teacher
evaluations during transition to a new assessment.)

tennessee Teacher Evaluations

50%

HOW IS TVAAS CALCULATED?
TVAAS uses data from Tennessee’s achievement tests to predict and assess
yearly growth for students across the state. To calculate yearly growth for
students, TVAAS looks at a student’s past testing data and predicts his or her
growth based on the average growth of students statewide with similar initial
levels of achievement.4 This component of the TVAAS model is meant to
ensure that a student's initial achievement level will not affect the accuracy of
the measure.
While other growth models explicitly adjust for students’ background characteristics such as race, ethnicity, and poverty status, TVAAS uses students’
prior achievement levels to account for these factors.5 A TVAAS score for a
teacher is determined by looking at the amount of growth that each of the
teacher’s students make in a given school year. Actual growth is compared to
the predicted growth to determine if each student’s growth was higher, lower,
or equal to what was expected.6

(FOR TEACHERS IN STATE-TESTED SUBJECT AREAS)

Other
Measures

Teachers were given
the option of having
TVAAS account for an
additional 15% of their
summative evaluation
scores if they scored a
3, 4, or 5 on TVAAS.

TVAAS Data

35%

For example, in Table 3 Student A’s sixth-grade test performance would generate a low TVAAS score, while Student B’s performance would result in a high
TVAAS score.

Other Student
Achievement Data

15%

Table 2