Background: A thorough understanding of the techniques underlying prognostic modelling, the potential shortcomings of prognostic models, and their applicability to dermatology are important for both clinicians and researchers.
Objective: This article distinguishes between prognostic and explanatory (causal) models, discusses some of the techniques used in developing a prognostic model, and addresses the importance of model generalizability.
Conclusion: Prognostic models may be useful to the clinician, but must be used with care. It is important to critically appraise prognostic models and to assure that they are relevant to the population of interest. The ability to critically appraise prognostic models is predicated on a thorough understanding of the techniques used in their development and evaluation.