The paper considers what is meant by, and the purpose of, blind modelling in the context of fire engineering. A discussion is presented on the very important interaction between the model and the model users, and five generic groups of model users are defined. The paper goes on to provide details of previous blind modelling studies from the literature, as well as a recent blind modelling programme that was conducted in New Zealand. A so-called ‘Openness Assessment Framework’ is proposed as a way of scoring or ranking existing or planned blind modelling programmes, with the recent New Zealand programme forming the case study for the evaluation. This framework is then applied to a range of evaluation definitions that are given in the literature, the five generic model user groups, as well as the range of blind modelling exercises already identified. Finally, a seven-step methodology for designing blind modelling studies and experimental comparisons in the context of full-scale multi-item compartment fire experiments is proposed.