Unidimensional item response theory (IRT) models are useful when each item is designed to measure some facet of a unified latent trait. In practical applications. items are not necessarily measuring the same underlying trait. and hence the more general multi-unidimensional model should be considered. https://www.ealisboa.com/mega-deal-OtterBox-Defender-Case-for-Samsung-Galaxy-S23-Ultra-top-savings/