TY  - JOUR
AU  - Jacob,Brian A.
AU  - Lefgren,Lars
AU  - Sims,David
TI  - The Persistence of Teacher-Induced Learning Gains
JF  - National Bureau of Economic Research Working Paper Series
VL  - No. 14065
PY  - 2008
Y2  - June 2008
UR  - http://www.nber.org/papers/w14065
L1  - http://www.nber.org/papers/w14065.pdf
N1  - Author contact info:
Brian Jacob
Gerald R. Ford School of Public Policy
University of Michigan
735 South State Street
Ann Arbor, MI 48109
Tel: 734-615-6994
Fax: NA
E-Mail: bajacob@umich.edu

Lars Lefgren
130 Faculty Office Bulding
Brigham Young University
Provo, UT 84602-2363
Tel: (801) 422-5169
E-Mail: l-lefgren@byu.edu

David Sims
130 Faculty Office Building
Brigham Young University
Provo, UT 84602-2363
E-Mail: davesims@byu.edu
AB  - 
Educational interventions are often narrowly targeted and temporary, and evaluations often focus on the short-run impacts of the intervention.  Insofar as the positive effects of educational interventions fadeout over time, however, such assessments may be misleading.  In this paper, we develop a simple statistical framework to empirically assess the persistence of treatment effects in education.  To begin, we present a simple model of student learning that incorporates permanent as well as transitory learning gains.  Using this model, we demonstrate how the parameter of interest – the persistence of a particular measurable education input – can be recovered via instrumental variables as a particular local average treatment effect.  We initially motivate this strategy in the context of teacher quality, but then generalize the model to consider educational interventions more generally.  Using administrative data that links students and teachers, we construct measures of teacher effectiveness and then estimate the persistence of these teacher value-added measures on student test scores. We find that teacher-induced gains in math and reading achievement quickly erode.  In most cases, our point estimates suggest a one-year persistence of about one-fifth and rule out a one-year persistence rate higher than one-third. 
ER  -