Editorial Commentary: Regression Modeling and Nomograms in Biomedical Research Are Valuable Decision-Making Tools...

The mathematical formulas underpinning biostatistical modeling in medical research can be complicated. Nomograms are pictoral tools showing a graphical solution of a formula in which all variables in the formula can be read off the diagram. Nomograms can be used to simplify the calculation of risk of recurrence of injuries or disease. Although nomograms can be valuable, external validation is required (of all models) to ensure accuracy outside of the original population, because variation in patient populations, activities, and risk behaviors outside of the patient data used in the original analysis may deteriorate model performance (external validity). A model also needs to be maintained over time to ensure continued accuracy as populations and activities change. A model that fails to keep up will eventually have its accuracy and clinical utility fade. An externally validated, well-maintained model can be a valuable tool for patient counseling and decision-making.