The NLIN procedure provides several experimental features for diagnosing your nonlinear model fit, including the PLOTS, NLINMEASURES, and BIAS options in the PROC NLIN statement, in addition to producing observation-wise statistics in the OUTPUT data set. The PLOTS option enables you to plot the fitted model, fit diagnostics, tangential and Jacobian leverage, and local influence. The NLINMEASURES displays global measures of nonlinearity, and the BIAS option computes Box’s bias statistics for the parameter estimates. Finally, you can add the leverage, local influence, and residual diagnostics in the output data set that is produced with the OUTPUT statement.