Monday, October 3, 2011

Measuring Student Growth with ATI’s Instructional Effectiveness Pretests and Posttests

A primary function of ATI’s Instructional Effectiveness (IE) assessments is to evaluate the amount of growth that students demonstrate between the pretest and the posttest. The IE posttests are comprised entirely of current grade-level content while the IE pretests contain both prior grade-level and current grade-level content. Many Galileo users may wonder how the assessments can measure growth, when part of the pretest was aligned to the prior grade-level.

The IE pretests and posttests can be used to measure growth because ATI uses state-of-the-art Item Response Theory (IRT) techniques to put the student development level (DL) scores for both the pretest and the posttest on a common scale so that the scores will be directly comparable. ATI DL scores are scale scores. The calculation of scale scores takes into account the relative difficulty of the items on the assessment. For example, imagine two students take two different tests. Both get 75% correct. If one test was much easier than the other assessment, then when the students’ ability levels (DL scores) are estimated, the one who got 75% correct on the easy test should have a lower ability estimate than the student who got 75% correct on the difficult assessment. Even though both have the same raw score, the student who took the easy test will have a lower DL score than the student who took the difficult test.

When DL scores are calculated for the pretests, the prior grade-level items are treated as if they were easy items. So even though the students should do very well on those items, their DL scores will be adjusted to a slightly lower level because the IRT analysis will see that the items were very easy. The DL scores will be on a scale that is directly comparable to the posttest, and there will be room for growth in DL scores between the pretest and the posttest. In other words, if a student gets exactly the same raw score (percent correct) on the pretest and the posttest, his or her DL score on the posttest will be higher than that on the pretest because the items on the posttest will be seen as being more difficult than the items on the pretest.

There are a number of ways to learn first-hand about the benefits both of Galileo K-12 Online and of measuring student growth with instructional effectiveness pretests and posttests. You can visit the Assessment Technology Incorporated website (, participate in an online overview by registering either through the website or by calling 1.877.442.5453 to speak with a Field Services Coordinator, or visit us at:

- Arizona School Administrators, Inc. (ASA) Fall Superintendency/Higher Education Conference, October 23 through 25 at the Prescott Resort and Conference Center, Prescott, Arizona
- Massachusetts Computer Using Educators (MassCUE) and the Massachusetts Association of School Superintendents (M.A.S.S.) Annual Technology Conference October 26 and 27 at the Gillette Stadium, Foxborough, Massachusetts
- Arizona Charter School Association (ACSA) 16th Annual Conference November 10 and 11 at the Westin La Paloma Resort, Tucson, Arizona
- Illinois Association of School Boards (IASB), Illinois Association of School Administrators (IASA), and Illinois Association of School Business Officials (IASBO) Joint Annual Conference November 18 through 20 at the Hyatt Regency Chicago, Chicago, Illinois

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