Comparing a single burst simulation for 10 Gyr old burst with alpha enhanced stars against all single age simulations as a test of the diagnostics. On the left are χ² diagnostics based on the I-band LF (upper left) and V-band LF (lower left). The upper right panel shows the diagnostic power of the full CMD fitting, while the lower right panel compares the number of red clump (RC) and AGB bump stars as a function of age. ΔN is the difference between the number of stars in the “input” (in this case simulation aen016) and the number of stars in the same boxes in the simulated CMD, normalized to the Poissonian noise of the number of “observed” (input) stars. Simulations constructed with α-enhanced isochrones are shown with red filled dots, and solar scaled models are plotted with blue open symbols.