Value-Added 

What is value-added?

Measuring an individual teacher’s impact on student learning can be challenging. After all, students start the year at different skill levels, and they all face different factors outside the classroom that can affect how they learn. 

At its core, value-added measurement is a way of dealing with these challenges. It helps us estimate the teacher’s impact on student learning as opposed to the impact of other factors such as students’ prior skill level, the resources they have at home, or any learning disabilities they may have. 

In short, value-added helps us understand what the teacher did, separate and apart from everything else. We can also calculate value-added at the school level, the only difference being we focus on the school’s collective contribution to student learning, as opposed to the teacher’s individual contribution.

How and why does DCPS use value-added data?

DCPS uses value-added data as part of “IMPACT,” our system for assessing teacher performance. We do so because we believe that clear evidence of student learning is an essential part of being an effective teacher. 

“Group 1” teachers, those who teach reading or math in grades four through eight, receive an Individual Value-Added (IVA) score, which accounts for 50% of their total IMPACT evaluation. 

In addition, all school-based personnel receive a School Value-Added (SVA) score, which accounts for 5% of their total IMPACT evaluation.

How does value-added work?

In short, we calculate how a teacher’s students are likely to perform, on average, on the DC CAS at the end of the year given their previous year’s scores and other relevant information. We then compare that likely score with the students’ actual average score. Teachers with high value-added scores are those whose students’ actual performance exceeds their likely performance.

Please note that the value-added calculation process is quite complex, which is why DCPS has contracted with Mathematica Policy Research, a nationally respected research firm, to conduct the analyses. Mathematica’s clients have included the United States Congress, the United States Department of Education, the National Academy of Sciences, and many other federal and state agencies.

Download Additional Information

For more detailed information about value-added, please download:

• The Value-Added Guidebook
•  The Value-Added Overview 
• Measuring School and Teacher Value Added for IMPACT and TEAM in DC Public Schools
  The 2009-10 technical report provides details of the model for calculating value-added scores for IMPACT and TEAM.
• Design of Value-Added Models for IMPACT and TEAM in DC Public Schools, 2010-2011 School Year
  This report highlights the small number of improvements made to the model in 2010-11.