Many educational leaders in states and districts throughout the U.S. view interim assessments as promising levers for increasing student achievement (Davidson & Frohbieter, 2011). The belief is that if objective data on student performance are available more frequently, then teachers possess evidence they can use to better diagnose changes in student learning and adjust instructional practices—and do so before state accountability tests are administered. However, there is mixed evidence of the effectiveness of this widely used approach.  The few well-executed quasi-experimental studies of interim assessments described in the literature have produced inconclusive findings (e.g., Henderson et al. 2007; Petrosino, Guckenburg, and Hamilton (2007); Quint, Sepanik, & Smith, 2008; Faria et. Al 2012.)

Randomized trials have been similarly inconclusive. Carlson, Borman, and Robinson (2011) report small but significant impacts of the 4Sight assessment program on mathematics achievement in grades 3 through 8, but not on reading. Konstantopoulos, Miller and van der Ploeg (2013) found significant treatment effects are detected in grades 3 to 8, especially in third and fourth grade reading and in fifth and sixth grade mathematics. However, Cordray, Pion, Brandt, and Molefe’s (2012) study in fourth and fifth grades in schools in Illinois districts found no impact on reading performance.

Another important premise about interim assessments, which has not been tested empirically, is whether such assessments can close the achievement gap. For instance, it is plausible that through interim assessments teachers identify instructional needs for low-achievers and modify their instruction accordingly to maximize performance for these students. To explore this issue, we examined the effects of interim assessments on mathematics and reading achievement using data from a large-scale cluster randomized experiment conducted in Indiana in 2009-2010. Our sample consisted of more than 20,000 students nested in more than 50 public k-8 schools in Indiana, that were randomly assigned to treatment (interim assessment programs - Acuity in grades 3-8, mCLASS in grades k-2) and control conditions. We employed quantile regression to examine treatment effects across the achievement distribution, and especially in the lower tail. If the treatment is more beneficial for low-achievers than other students one would expect larger treatment estimates in the lower tail of the achievement distribution. We conducted both Intention to Treat (ITT) and Treatment on the Treated (TOT) analyses.

Both ITT and TOIT analyses produced treatment effects that were typically larger for low-achievers than for other students and in some cases they were significant. These effects were observed both in mathematics and reading in grades 3 to 6. However, the evidence was not consistent and strong.  It seems that mCLASS (gradesK-2) did not affect mathematics or reading achievement significantly, while Acuity (grades 3-8) seems to have affected mathematics and reading achievement positively, especially in the lower tails, and in some instances considerably in upper grades. Thus, this study provides some empirical support to the hypothesis that interim assessments should produce additional benefits for low-achievers and as a result potentially reduce the achievement gap.