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Fig. 1 | Measurement Instruments for the Social Sciences

Fig. 1

From: Why ability point estimates can be pointless: a primer on using skill measures from large-scale assessments in secondary analyses

Fig. 1

A latent measurement model in CTT notation. The latent ability θ is measured by k test items (manifest indicators Y1 … Yk). The different loadings λ1…λk and measurement error terms ε1 … εk reflect different degrees to which each item reflects the latent ability. For substantive analyses and/or for estimating PVs, θ can be predicted by background variables (X1…Xp). The latter model part is often referred to as the population model (e.g., Mislevy, 1991)

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