The HFACS model was designed to be a classification tool rather than a predictive tool. However, since its initial development, there has been a lot of interest on whether it can also be used as a predictive tool. That is, can it be used to inform us about which factors in preconditions for unsafe acts, unsafe supervision, and organizational influences predict factors within unsafe acts?
A major assumption underpinning the HFACS model is that there is a causal or, at least, a predictive relationship between factors in the upper levels to those in the lower levels. For instance, organizational influences are presumed to affect the likelihood of unsafe supervision, which in turn influences preconditions for unsafe acts, which in turn influences the likelihood of unsafe acts. Another assumption is that all factors within a level are independent of each other.
There is little evidence of whether HFACS (or other similar models based on the Reason (1990) accident causation model) can be used to predict relationships between contributing factors.