We propose simplified metrics to evaluate the fidelity with which the Madden-Julian oscillation (MJO) is simulated in climate models. These metrics are based on lag correlation analysis of principal component time series (PC’s). The PC’s are obtained by projecting simulated 20-100 day bandpass filtered daily outgoing longwave radiation onto the two leading empirical orthogonal functions of observed MJO variability. The simplified MJO metrics, the maximum positive correlation and time lag at which it occurs, provide consistent information relative to more complex diagnostics developed by the Madden-Julian Oscillation Working Group (CLIVAR MJOWG, 2009; Kim et al., 2009).