Technical Manual - Renaissance Learning

ValidityPost-Publication Study DataAs shown in Table 25, for tests given in Fall 2003 the correlation coefficientsbetween the MLPP tests and STAR Early Literacy Scaled Scores were between 0.56and 0.82; all are statistically significant. The strength of this relationship indicatesthat STAR Early Literacy measures a significant number of the same skillsmeasured by the MLPP tests. For Spring 2004 scores, the range of correlations issimilar. Most of the Spring 2004 correlations have been corrected for rangerestriction, to account for ceiling effects 6 on the MLPP tests. Ceiling effectsaffected all but two of the Spring 2004 MLPP tests (Word Lists and Known Words.)To estimate what the correlation would have been had there been no ceiling effecton the MLPP tests, the McNemar correction formula was applied. It takes intoaccount the variance of scores in both Fall and Spring. The correction was notapplied to correlations with the two MLPP tests for which the ceiling effect was notevident.A complete description of the MLPP Validation Study, including correlation ofMLPP tests with STAR Early Literacy Domain Scores, is presented in CorrelationBetween Michigan Literacy Progress Profile and STAR Early Literacy, an April 2005report. To request a free copy, call Renaissance Learning at 1-800-338-4204.Table 25:STAR Early Literacy Scaled Score Correlations with Michigan LiteracyProgress Profile Raw Scores, Combined K and 1Fall 2003 Spring 2004TestN r N rConcepts of Print 245 0.74 219 0.74Letter Name 245 0.76 219 0.72Letter Sounds 245 0.80 219 0.74Word List 245 0.62 219 0.81Known Words 245 0.70 219 0.66Rhyming 245 0.56 219 0.53Dictation 245 0.82 219 0.76Segmenting 245 0.69 219 0.57Blending 245 0.71 219 0.736. Ceiling effects occur when the overall ability level of students exceeds the difficulty level of the testitems, resulting in a score distribution with a large proportion of the students attaining the highestpossible scores on the test. Ceiling effects attenuate the magnitudes of correlation coefficients byreducing test score variance. A statistical “correction for range restriction” is intended to correctthis.STAR Early LiteracyTechnical Manual68