Why Measure Growth

ETS · October 2009

Why Measure Growth — ETS, October 2009.
Published

October 24, 2009

Event
Invited talk
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4
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Converted from PowerPoint

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Slide text
  1. Why Measure Growth • Student learning is a central goal of education • Assessments of student achievement provide evidence of current status of student knowledge and understanding • Learning is demonstrated by growth in student achievement from one point in time to a another point in time – not by status at either point time alone
  2. Uses of Growth Measures • Informing students, parents, and teachers about individual student progress – Measuring individual student growth can be useful, but utility is limited due to low reliability of individual student gain scores • School accountability systems – Growth measures have substantial advantages over status measures for accountability – Unlike status measures, growth takes prior achievement into account
  3. Growth vs. Value Added • Value-added models attempt to make causal attributions • Growth measures are purely descriptive • In the absence of random assignment causal attributions are always suspect and subject to challenges (see, for example, Raudenbush, 2004; Rubin, Stuart & Zanutto, 2004)
  4. Interpreting Growth Measures Physical growth Achievement growth • 9 year old boy grew 5 measure inches in past year (is that • 4th grader grew 25 scale a lot or a little?) score points since 3rd grade (Is that a lot or a little? • Average 4th grade scale • Relative interpretation is score is 21 points higher easier than absolute than average 3rd grade (Average height of 9 year score, the gain of 25 boys is 49 inches points is at the 65th compared to 45 inches for percentile) 8 year old boys, the 5 inch growth is at the 65th percentile)