Psychometricre construction of the inquiry science teaching strategies (ISTS) instrument

Abstract

This study re-evaluated the psychometric properties of the 40-item Inquiry Science Teaching Strategies instrument [ISTS] (Lazarowitz & Lee, 1976). The ISTS was administered to 201 elementary pre-service teachers at a university in the Midwest of United States during the 2009-2010 school terms. Initial CFA results failed to confirm the 3-factor structure of the original ISTS. A statistically significant goodness-of-fit statistic (χ 2 [737, N = 201] = 1394.61, p = 0.00) supported by two fit indices (GFI = 0.69, CFI = 0.45) indicated non-tenability of the measurement model. Subsequent PCA retained half of the components under an obliquely rotated 3-factor solution. Following the removal of 22 items, final CFA indicated non-tenability under slightly improved fitting (χ 2 [132, N = 201] = 236.93, p = 0.00, GFI = 0.88, CFI = 0.83). It is recommended that existing items be revised and new ones appended using Exploratory Factor Analysis with a different sample.