How can scaled scores be compared across time?

This article is intended only for customers and partners using the Assessment Series.

The scaled scores on CommonLit's Assessment Series tests account for both the number of questions students answered correctly on a test and the difficulty of the questions on a test. That means that, even if one test is slightly easier or harder than another, students' scaled scores can be compared across those two tests. In other words, if a student’s score increases significantly from the Pre-Assessment to the Post-Assessment and the assessments were given under consistent conditions, that change can be more directly attributed to an increase in the student’s reading ability.

Student scores can also fluctuate slightly between each administration of an assessment because of a number of factors (e.g., their level of concentration on a given day), so small changes in student scores from the Pre- to the Post-Assessment are not indicative of either growth or decline in student ability. CommonLit’s data displays indicate what amount of growth is considered "significant" in each grade level.