We measure per-word-type performance using AUC, which is word-frequency independent.
-for each word type w (e.g., w = beer) we measure how well w is predicted by the classifier based on ASR / spoken tokens AUC t,w (e.g., AUC t,beer = 98) and, conversely, how well w is predicted by the visual classifier AUC v,w (AUC v,beer = 68).