Insight Psychometrics Technical Manual - Canadian Test Centre

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Figure 19: Differential item functioning in the final development items in Gc,Gv, and Gf.Differential item functionning−10 −5 0 5 10Gc 1 Gc 2 Gc 3 Gv 1 Gv 2 Gv 3 Gf 1 Gf 2 Gf 3Scale and levelConcurrent validityFor subsamples of examinees in the initial development sample of Insight,information was also obtained for the WISC IV test (N=75) and for theWoodcock- Johnson III Tests of Cognitive Abilities (N=72). In Figure 20 acomparison is made of the most general scores: the Woodcock-Johnson IIIGeneral Intellectual Ability, the WISC IV Full Score, and the Insight AbilityScore (IAS) from Insight. More detailed analysis with these small subsamplesdid not seem to be warranted. Generally, the correlation of Insight IAS andWISC IV Full Score is very high (r=.88), practically at the limit of what canbe expected given the measurement errors in the two tests. The correlationwith Woodcock-Johnson III is lower (r=.62) and, from the scatterplot, it seemsthat there is some difference in the scaling and that some part of thesubsample is not following the trend line. This requires further data forinvestigation, but given the high correlation of Insight and WISC IV, it mightbe useful to have data that has all three scores on the same sample ofexaminees.19
Figure 20: Insight compared to WISC IV and Woodcock-Johnson IIIWJ.GENERAL.INTELLECTUAL60 80 100 120 140WISC.FULL.SCALE60 80 100 120 14060 80 100 120 140IAS60 80 100 120 140IASInternal correlation structureThe intercorrelations of the Insight standard scores (age normed) werepresented earlier in Figure 17. These are repeated in Figure 21, together withthe intercorrelations of the original vertically equated and unnormed Raschtheta scores. The purpose of this juxtaposition is to consider the internalfactor structure of the Insight subtest set of scores. The standard scorecorrelations show relatively low and homogeneous correlations, which areconsistent with independent traits with a common underlying factor. Onlythe Processing Speed subtest, Gs, has a substantially lower correlation withthe others. The Rasch thetas have higher intercorrelation, and this due to thecommon effect of growth and change with age.20
Page 1 and 2: InsightTechnical ManualRichard Wolf
Page 3 and 4: Table of figuresFigure 1 Test level
Page 5 and 6: 29 in Level 2. Notice that some ite
Page 7 and 8: Development stepsThe items were wri
Page 9 and 10: Figure 11: Regional Anglophone popu
Page 11 and 12: Practically, this means that the Le
Page 13 and 14: Figure 13: Glr regression by age an
Page 15 and 16: 6) From the final scores, national
Page 17 and 18: Statistical analysesItem statistics
Page 19 and 20: of the correlations of the underlyi
Page 21: Validity analysesCheck on gender bi
Page 25 and 26: Connection to Canadian Achievement
Page 27 and 28: Figure 25: Standard errors of measu
Page 29: Appendix A. Item locations and stan
Page 51: Appendix C. Item-age regressions fo

Insight Psychometrics Technical Manual - Canadian Test Centre

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