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The Reliability and Consequential Validity of Two Teacher-Administered Student Mathematics Diagnostic Assessments

Region:
Southeast
Description:

Several school districts in Georgia currently use two teacher-administered diagnostic assessments of student mathematical knowledge as part of their multi-tiered system of support in grades K–8. These assessments are the Global Strategy Stage (GloSS; New Zealand Ministry of Education, 2012) and the Individual Knowledge Assessment of Number (IKAN; New Zealand Ministry of Education, 2011). However, little is known about the inter-assessor reliability and consequential validity of these assessments. Inter-assessor reliability indicates whether two teachers obtain the same score for a student after administering the test on two occasions, and consequential validity explores perceptions of the value of using the assessments. Rather than rely on occasional testimonials from the field, decisions about using diagnostic assessments across the state should be based on psychometric data from an external source. Districts not currently using the GloSS and IKAN have indicated that they would consider using them to assess students’ current level of mathematical understanding and determine appropriate levels of instruction and intervention, if they were proven to be reliable and valid diagnostic assessments. This study found that the inter-assessor reliability for the GloSS measure and the IKAN Counting Interview is adequate. The inter-assessor reliability for the IKAN Written Assessment (one of the two components of the IKAN) is inadequate, and additional attention must be directed toward improving training for this measure so that reliability can be established. Teachers indicated that they found the data from the GloSS and IKAN assessments more useful than screening data currently in use for guiding decisions about how to provide intervention. Although teachers interviewed in the study’s focus groups expressed strong support for using both assessments, they reported in the study survey that the GloSS is more useful than the IKAN because it addresses students’ solution strategies, which most other mathematics measures do not assess. Teachers did express some criticisms of both assessments; for example, they felt the IKAN Written Assessment should be untimed and that the GloSS should include familiar vocabulary.

Publication Type:
Descriptive Study
Online Availability:
Publication Date:
September 2020