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.roneverhart.com/Madrid-The-Leadfoot-Zak-Maytum-Pro-Model-32-Freeride-Deck-Performance-Series/