An aspect of a study is considered a confounding factor if it is not possible to tell whether the difference in outcomes is due to the intervention, the confounding factor, or both. In What Works Clearinghouse (WWC) study reviews, certified reviewers look for a specific type of confounding factor: those that occur when a component of the study…

The What Works Clearinghouse (WWC) uses the term "baseline equivalence" when determining if the intervention group (those that received the intervention of interest) and the comparison group (those that did not receive the intervention) had characteristics that were similar enough ("equivalent") at the start of the study (at…

The What Works Clearinghouse (WWC) Standards Briefs explain the rules the WWC uses to evaluate the quality of studies for practitioners, researchers, and policymakers. This brief explains what baseline equivalence is and why it matters. As part of the WWC review process for certain types of studies, reviewers assess whether the intervention group…

"DreamBox Learning" is a supplemental online mathematics program that provides adaptive instruction for students in grades K-5 and focuses on number and operations, place value, and number sense. The What Works Clearinghouse (WWC) identified one study of "DreamBox Learning" that both falls within the scope of the Elementary…

"DreamBox Learning" is a supplemental online mathematics program that provides adaptive instruction for students in grades K-5 and focuses on number and operations, place value, and number sense. The What Works Clearinghouse (WWC) identified one study of "DreamBox Learning" that both falls within the scope of the Elementary…

"Late Interventions Matter Too--The Case of College Coaching in New Hampshire" examined whether providing college application coaching to high school seniors increased postsecondary enrollment. The program was aimed at students who were considering applying to college but who had made little or no progress in the application process, and…

For the 2014 study, "The Iterative Development and Initial Evaluation of We Have Skills!, an Innovative Approach to Teaching Social Skills to Elementary Students", researchers examined the effects of We Have Skills! (WHS), a supplemental, video-based social skills program for early elementary students. WHS consists of three components:…

The study, "The Impact of Indiana's System of Interim Assessments on Mathematics and Reading," examined the effects of using Diagnostic Assessment Tools (DAT) on mathematics and reading outcomes for students in 59 Indiana schools during the 2009-10 academic year. DAT consists of interim assessment tools--Wireless Generation's mCLASS for…

The 2011 study, "Benefits of Practicing 4 = 2 + 2: Nontraditional Problem Formats Facilitate Children's Understanding of Mathematical Equivalence," examined the effects of addition practice using nontraditional problem formats on students' understanding of mathematical equivalence. In nontraditional problem formats, operations appear on…

The study authors examined the impact of "Responsive Classroom," a professional development program for teachers, on student achievement. This study took place in a large, ethnically and socioeconomically diverse district in a mid-Atlantic state. The intervention was implemented during 3 school years from 2008 to 2011. Study authors…

"Spelling Mastery" is designed to explicitly teach spelling skills to students in grades 1 through 6. One of several Direct Instruction curricula from McGraw-Hill that precisely specify how to teach incremental content, "Spelling Mastery" includes phonemic, morphemic, and whole-word strategies. The What Works Clearinghouse…

For the 2013 study, "Transfer Incentives for High-Performing Teachers: Final Results from a Multisite Randomized Experiment," researchers examined the impact of the Talent Transfer Initiative (TTI) on students' reading and mathematics achievement in 10 school districts. The TTI enabled principals of low-performing schools to provide…

The 2013 study, "Interactive Learning Online at Public Universities: Evidence From a Six-Campus Randomized Trial," examined the impact of interactive learning online (ILO) on the pass rates of 605 students enrolled in introductory statistics courses at six public universities. ILO is a form of online course instruction in which…

The study reviewed here examined the effect of charter schools on annual student achievement growth in reading and math in 25 states, the District of Columbia, and New York City. The study primarily used data on students in grades 3-8, but additional elementary and high school grades were included for several states. The authors reported that…

"Check & Connect" aims to help students stay in school by continually monitoring school performance and providing individualized attention through mentoring, case management, and other supports. In 2006, the WWC published a systematic review of all the studies that examined the impact of "Check & Connect" on high school…