Where was this model first introduced?

Principles of Property Investment and Pricing by W.D. Fraser (1984)

How accurate is the model?

The accuracy of commercial property market models, like any financial or economic models, varies widely. These models are tools used to predict future market trends, assess property values, or make investment decisions, but their precision and reliability can be influenced by the quality and availability of data, the model’s assumptions, market volatility and external factors, regional and sector-specific variations, temporal dynamics.