The Diffusion Areas Model clarifies how to measure BIM Diffusion across markets. Rather than just counting how many software licences are sold across a market, this model identifies 9 different metrics by overlaying top-level BIM topics (technology, process and policy) over BIM capability stages (modelling, collaboration and integration).
Additional information covering this model is provided on the BIM Framework blog: http://www.bimframework.info/2015/05/diffusion-areas.html.
Source