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KIPP Middle Schools: Impacts on Achievement and Other Outcomes
Last registered on February 24, 2015


Trial Information
General Information
KIPP Middle Schools: Impacts on Achievement and Other Outcomes
Initial registration date
February 24, 2015
Last updated
February 24, 2015 2:00 PM EST
Primary Investigator
Mathematica Policy Research
Other Primary Investigator(s)
PI Affiliation
Mathematica Policy Research
PI Affiliation
Mathematica Policy Research
Additional Trial Information
Start date
End date
Secondary IDs
Using experimental and quasi-experimental methods, this report shows that Knowledge is Power Program (KIPP) middle schools have significant and substantial positive impacts on student achievements in four core academic subjects: reading, math, science, and social studies. One of the report’s analyses uses a rigorous randomized experimental analysis that relies on the schools’ admissions lotteries to identify comparison students, thereby accounting for students’ prior achievement, as well as factors such as student and parent motivation. The study is the most rigorous large-scale evaluation of KIPP charter schools to date. Student outcomes examined in the experimental component of the study included reading and math scores on a nationally normed assessment that includes measures of higher-order thinking, and behaviors reported by students and parents.
External Link(s)
Registration Citation
Gill, Brian, Philip Gleason and Christina Tuttle. 2015. "KIPP Middle Schools: Impacts on Achievement and Other Outcomes." AEA RCT Registry. February 24. https://doi.org/10.1257/rct.638-1.0.
Former Citation
Gill, Brian et al. 2015. "KIPP Middle Schools: Impacts on Achievement and Other Outcomes." AEA RCT Registry. February 24. http://www.socialscienceregistry.org/trials/638/history/3660.
Experimental Details
The intervention is the offer to attend an oversubscribed Knowledge Is Power Program (KIPP) middle school. KIPP is a rapidly expanding network of public charter schools whose mission is to improve the education of low-income children. As of the 2012–2013 school year, 125 KIPP schools were in operation in 20 different states and the District of Columbia (DC). Ultimately, KIPP’s goal is to prepare students to enroll and succeed in college.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
1. Math and reading test scores one year and two years after baseline. (10 schools )
2. Student behavior and attitudes based on parent and student surveys administered two years after admission lotteries. These outcomes cover four domains: i. Student engagement and effort in school; ii. Educational aspirations and expectations; iii. Student well-being and behavior and; iv. Satisfaction with and perceptions of school. (13 schools)
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
KIPP middle schools with more applicants than available seats often admit students using a random lottery. Records from these lotteries can be used to conduct a randomized experiment as students who participated are offered KIPP admission completely by chance. For 10 of the 13 middle schools, experimental treatment and control status were determined by whether the student received an admission offer by October 15 (in 2008 for cohort 1; in 2009 for cohort 2). For the 3 remaining schools that ultimately exhausted waitlists, we implemented an alternative experiment wherein treatment status is defined based on the initial lottery outcome rather than post-lottery waitlist offers.
Experimental Design Details
Randomization Method
Randomization conducted by individual schools.
Randomization Unit
The unit of randomization and of intervention is the student.
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
13 schools, 2 cohorts, 2 grades
Sample size: planned number of observations
Middle schools: 535 treatment students, 644 control students
Sample size (or number of clusters) by treatment arms
19 school-cohort-grade combinations (both treatment and control)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB Name
New England Institutional Review Board
IRB Approval Date
IRB Approval Number
Post Trial Information
Study Withdrawal
Is the intervention completed?
Intervention Completion Date
June 01, 2011, 12:00 AM +00:00
Is data collection complete?
Data Collection Completion Date
Final Sample Size: Number of Clusters (Unit of Randomization)
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
Final Sample Size (or Number of Clusters) by Treatment Arms
Data Publication
Data Publication
Is public data available?
Program Files
Program Files