The Early Development Instrument: An Examination of Convergent and Discriminant Validity Shelley Hymel • Lucy LeMare • William McKee Accepted: 22 October 2010 / Published online: 7 June 2011 Ó Springer Science+Business Media B.V. 2011 Abstract The convergent and discriminant validity of the Early Development Instrument (EDI), a teacher-rated assessment of children’s ‘‘school readiness’’, was investigated in a multicultural sample of 267 kindergarteners (53% male). Teachers evaluations on the EDI, both overall and in five domains (physical health/well-being, social competence, emotional maturity, language/cognition, communication/general knowledge), were related to direct, child-based assessments of performance on two standardized measures of school readiness, and measures of phonological awareness and early social competence. Regression analysis indicated that together the four comparison measures accounted for 36% of variance in overall EDI scores, each making a significant and unique contribution. Results supported the convergent validity of overall EDI scores but not the discriminant validity of EDI domain scores. Moreover, correlations between EDI scores and comparison measures varied widely across teachers, suggesting considerable individual differences in teacher’s ability to evaluate school readiness relative to direct, child-based assessments, and con- firming that the EDI is more appropriate for deriving inferences at higher aggregated levels Portions of this paper were presented at the January 18, 2005 meeting of the Human Early Learning Partnership, University of British Columbia, Vancouver, BC, at the EDUDATA CANADA Research Forum, May 5, 2006, Vancouver, BC, and at the April 2006 meeting of the American Educational Research Association, as part of a symposium organized by Martin Guhn entitled, ‘‘Translating school readiness assessment into community actions and policy planning: The Early Development Instrument Project’’. San Francisco, CA. S. Hymel Á W. McKee Department of Educational and Counselling Psychology and Special Education, University of British Columbia, Vancouver, BC, Canada e-mail: william.mckee@ubc.ca L. LeMare Faculty of Education, Simon Fraser University, Burnaby, BC, Canada e-mail: lemare@sfu.ca S. Hymel (&) Faculty of Education, University of British Columbia, 2125 Main Mall, Vancouver, BC V6T 1Z4, Canada e-mail: shelley.hymel@ubc.ca 123 Soc Indic Res (2011) 103:267–282 DOI 10.1007/s11205-011-9845-2