Slide 36: Kappa statistic
From the misclassification matrix a function such as the Kappa statistic can be calculated. This function takes the possibility of chance agreements into account. The kappa statistic is calculated for a range of threshold values, and the best threshold value is kept as a reasonable predictor of species presence.
The value of a model's predictions is assessed on a scale between 0 and 1. Anything over 0.7 is a good model, models below 0.4 are a poor fit, and anything between these levels is considered a reasonable fit.