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Multivariate Methods > Item Analysis > Statistical Details for the Item Analysis Platform
Publication date: 09/28/2021

Statistical Details for the Item Analysis Platform

Item response theory (IRT) uses a series of equations to relate items to an unobserved (latent) trait or ability. Items, or questions, are indicators of an underlying latent construct that cannot be directly observed. At the time of data collection, both the subject abilities and the item characteristics are unknown.

Item Response Curves

Item Response Curve Models

IRT Model Assumptions

Fitting the IRT Model

Ability Formula

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