Analytic approaches for the evaluation of costs.

Currently, economic evaluation of new medical therapies is conducted routinely. Development of an analysis plan before performance of the analysis is a first step in the analysis of data from such evaluations. Univariate analysis of costs can be performed with both parametric and nonparametric tests. Potential multivariable analyses include ordinary least squares regression, nonparametric hazard models, parametric failure time models, Cox semiparametric regression, and joint distributions of survival and cost. In addition to developing point estimates for economic outcomes, 95% confidence intervals for cost-effectiveness ratios should be developed to evaluate the level of uncertainty that surrounds these estimates. Sensitivity analysis should be used to address other sources of uncertainty.