Note(s): For each coefficient estimate the accompanying standard error (SE), zvalue and p-value are also given. The model is a logistic mixed effects model with book ID as random effect on the intercept. It was selected from the set of models with all combinations of three additive variables created from the available predictor variables (see Table 1), using the AICc as selection criterion. The variables were ztransformed before model fitting, so that the size of the parameter estimates reflects variable importance. The marginal R-squared for this model is 0.05, while the conditional R-squared is 0.25