A critique of the expectancy formula approach: Beating a dead horse?

The expectancy and severe discrepancy formulas, like those originally considered by the US. Office of Education (1976), provide the oldest but least defensible method of quantifying academic discrepancy. A logical and mathematical analysis reveals that all variations of this approach have several major weaknesses. First, the expectancy formulas themselves are predicated upon the very questionable assumption that achievement follows a straight line growth pattern, which raises questions about the accuracy of the resulting severe discrepancy values. Second, when discrepancy values are obtained by multiplying the expected values by a fractional constant, the approach is necessarily biased in the direction of applying a more stringent underachievement criterion for older and brighter children. Third, the formulas employ a grade equivalent scale that results in inconsistencies, one being that fewer arithmetic problems are identified. Finally, the expectancy approach does not consider errors in measurement or regression effects, and consequently produces serious identification errors. A variation of the expectancy approach involving a discrepancy ratio between obtained and expected achievement has the previously mentioned limitations, except the bias, and it produces scores that cannot be easily interpreted.     

A Bridge to Developing Efficacious Science Teachers of All Students: Community-Based Service-Learning Supplemented with Explicit Discussions and Activities about Diversity

This study explored the effects of community-based service-learning (CBSL), supplemented with discussions and activities about diversity, on the self-efficacy beliefs of preservice elementary teachers regarding equitable science teaching and learning for diverse student groups. The study was conducted with 81 preservice teachers enrolled in four sections of an elementary science methods course over a semester. Employing a mixed-methods research design, data were collected using pretests–posttests with the study sample and semistructured interviews with a subsample. The results support the value of preservice teachers engaging in CBSL experiences, supplemented with discussions and activities about diversity, as a way to improve their self-efficacy beliefs regarding equitable science teaching and learning of all students.