DIBELS/CTOPP 1 Running head: CONCURRENT VALIDITY & DIAGNOSTIC ACCURACY Concurrent Validity and Diagnostic Accuracy of the Dynamic Indicators of Basic Early Literacy Skills and the Comprehensive Test of Phonological Processing

The purpose of this study was to: (a) examine the concurrent validity of the DIBELS with the CTOPP, and (b) explore the diagnostic accuracy of the DIBELS in predicting CTOPP performance using suggested and alternative cut-scores. Eighty-six students were administered the DIBELS and the CTOPP in the winter of their Kindergarten year. Patterns of correlations between the two sets of measures were examined and decision accuracy studies conducted based on suggested cut-scores and cut-scores determined as a result of Receiver Operator Characteristic (ROC) curve analysis. Results showed moderate to strong correlations between the DIBELS and the CTOPP suggesting that both measure a similar construct. Analysis of decision accuracy indicated that using the author suggested cut-scores resulted in extremely high sensitivity, however this was at the expense of an inordinate number of false-positives. Follow-up analyses using adjusted cut-scores improved specificity and positive predictive power, reduced falsepositives, and increased the number of correct classifications sizably.