Goodness of fit In this study two measures of goodness of fit will be used, primarily driven by the need for such measures to be easily comprehensible and have been used in other studies to put these results in context. e first is simply the correlation squared between the observed rental price and the out of sample appraised price. is is described as the r2 statistic here. the second measure is the percentage error in the prediction, measured as the absolute difference between the listing price and the out-of- sample appraised price, divided by the listing price. is statistic is summarised as its median (the lower the median the better) and also as the proportion of these percentage errors below certain thresholds (the higher the proportion the better). these two measures are distinct from the RMSE calibration statistic and also readily comprehendible to the lay person.