The nomographic display of the individual and cumulative inputs is evaluated stepwise via the calculation of likelihood ratios applied incrementally with a Fagan's Nomogram (Fagan TJ; 1975) to produce an overall predictive index beginning with a calculated base rate, and combining the results of the other measures, in either an additive or subtractive manner, to provide a post-test probability. When used in conjunction with clinical judgment, these components have proven to be highly effective for consideration of diagnosis and in highlighting and documenting a need for further evaluation or actions, and may allow the clinician to evaluate their own diagnostic practices and effectiveness over time.
