Title: Validation of longitudinal achievement constructs of vertically scaled computerised adaptive tests: a multiple-indicator, latent-growth modelling approach

Authors: Shudong Wang; Hong Jiao; Liru Zhang

Addresses: Northwest Evaluation Association (NWEA), 121 NW Everett St., Portland, OR 97206, USA ' Department of Human Development and Quantitative Methodology, University of Maryland, College Park, MD 20742, USA ' Delaware Department of Education, 401 Federal Street, Suite 2, Dover, DE 19901, USA

Abstract: It is a commonly accepted assumption by educational researchers and practitioners that an underlying longitudinal achievement construct exists across grades in K-12 achievement tests. This assumption provides the necessary assurance to measure and interpret student growth over time. However, evidence is needed to determine whether the achievement construct remains consistent or shifts over grades or time. The current investigative study uses a multiple-indicator, latent-growth modelling (MLGM) approach to examine the longitudinal achievement construct and its invariance for the measures of academic progress® (MAP®), a computerised adaptive test in reading and mathematics. The results of the analyses from ten states suggest that with repeated measures, the construct of both MAP reading and mathematics remained consistent at different time points. The findings support the achievement construct's invariance throughout different grades or time points and provide empirical evidence for measuring student growth.

Keywords: validity; longitudinal achievement construct; computerised adaptive tests; CAT; multiple-indicator latent-growth modelling; MLGM; K-12 achievement tests; reading tests; mathematics tests; student growth measurement; academic progress measures.

DOI: 10.1504/IJQRE.2013.058307

International Journal of Quantitative Research in Education, 2013 Vol.1 No.4, pp.383 - 407

Available online: 12 Dec 2013 *

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