DACEHTA, Denmark
Generalisability and transferability both refer to the degree to which results of an HTA can be extrapolated to other circumstances or settings. The two terms are often seen as having the same meaning, and are very closely related. It could however be desirable to ascribe different meaning to the terms. One possible way of separating the two terms is as follows:
Generalisability basically refers to the external validity of an HTA. In general this refers to both interventions, outcomes, units and settings. Generalisability as a concept grows out of research methodology
Transferability refers to the organisational context dependent questions. Is it possible to envision transfer to another setting based on the information in the HTA? Transferability grows out of policy analysis / political science.
Transferability can be seen as a subcategory of generalisability. It is however extremely important to focus on the transferability (setting) question when it comes to adaptation (especially concerning organisational questions) since the selection of relevant HTAs (or other parts of the HTAs than the core) for adaptation relies heavily on an assessment of the context dependent parts of the HTA. Furthermore it is important to stress that question of generalisability both include statistical and analytical generalisation; external validity and construct validity.
Another interpretation of transferability (often used in organisational theory) could be that it is not as closely related to generalisability, but rather related to the description of the process of transferring one idea, in this case the HTA report, from one field to another.