χ² goodness of fit measurements and fitted spectra for the reduced-cloud Venus model (top), the cloudy Venus model with a reduced-cloud prior (middle) and the cloudy Venus model with a cloudy prior (bottom). The best-fitting model in each case is indicated by a dashed line on the χ² plot. For the cases where the cloud prior used matched the true conditions well, a better fit is found for Venus-type model atmospheres, but in the case where the prior underestimates the cloud optical depth (middle plots) the spectrum would be incorrectly identified as Earth-like.