Student Outcomes

Types of ISAT Studies

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Controlled Regression Studies

Sidebar: What did these regression studies tell us?

Evaluators used a multivariate interrupted time series experiment (ITSE) to assess how cohorts performed relative to comparison groups when multiple factors were controlled. These analyses looked at three things:

The analyses employed the following 11 independent control variables. The variables included controls for

Racial groupings:

And the following individual differences: Still, the findings of the “Controlled Regression” analyses must be viewed cautiously because they were based on only three data points from within a larger, ongoing pool of test scores. Without additional years of data one needs to be cautious in drawing definitive conclusions. Additional years of data would likely make the long-term trends clearer. At a minimum, this research should be expanded to include several years of data prior to the start of CMSI-supported materials implementation. This would facilitate a better understanding of actual (mean) performance prior to the onset of the implementation. However, the change from the IGAP to the ISAT in academic year 1999-2000 left only four “pre-implementation” years with similar ISAT test data available, and those were only relevant to Cohort #3. Cohort #2 had three years of pre-program data and Cohort #1 only two. This reflects the staggered nature of the cohort implementation process.

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This was because in 2005-2006 the ISBE redesigned the ISAT and instituted a single linear scale for ISAT scores regardless of grade, and all prior year scores were equated to the new index.