Insight Psychometrics Technical Manual - Canadian Test Centre

Development stepsThe items were written by Dr. A. Lynne Beal and Dr. Rhia Roberts. The items ineach subtest pool were subsequently assigned to three different difficulty levelsbased on the apparent relative difficulties of the items. (After the first field test,items were assigned to levels based on empirically based difficulty estimates.) Thedistribution of items by level and subtest for the current (final) Insight test formsare given in Figure 2 above. During the development and norming stages of Insight,there were two earlier sets of forms. In the initial development forms, most subtestshad substantially more items, as shown in Figure 1, because an important goal wasto gain information about many items and then use the information to constructmore efficient smaller forms.Figure 1: Subtests and number of items by level for the initial developmentformsNumber of itemsLevel 1 Level 2 Level 3Crystallized Knowledge (Gc) 50 50 50Visual Processing (Gv) 50 50 50Fluid Reasoning (Gf) 30 40 50Short-Term Memory (Gsm) 50 50 50Long-Term Memory Retrieval (Glr) 36 48 72Auditory Processing (Ga) 50 50 50Processing Speed (Gs) 49 56 70In the next stage, a careful selection of items was made, keeping those that had thebest statistical properties (e.g., high discrimination). This led to a new set ofdevelopment forms, with items by subtest and level as show in Figure 2.Figure 2: Subtests and number of items by level for the later developmentformsNumber of itemsLevel 1 Level 2 Level 3Crystallized Knowledge (Gc) 35 40 40Visual Processing (Gv) 30 30 30Fluid Reasoning (Gf) 42 47 47Short-Term Memory (Gsm) 20 24 24Long-Term Memory Retrieval (Glr) 36 48 72Auditory Processing (Ga) 20 24 24Processing Speed (Gs) 42 49 494