Evaluating Classification Consistency of Oral Lesion Images for Use in an Image Classification Teaching Tool

A web-based image classification tool (DiLearn) was developed to facilitate active learning in the oral health profession. Students engage with oral lesion images using swipe gestures to classify each image into pre-determined categories (e.g., left for refer and right for no intervention). To assemble the training modules and to provide feedback to students, DiLearn requires each oral lesion image to be classified, with various features displayed in the image. The collection of accurate meta-information is a crucial step for enabling the self-directed active learning approach taken in DiLearn. The purpose of this study is to evaluate the classification consistency of features in oral lesion images by experts and students for use in the learning tool. Twenty oral lesion images from DiLearn's image bank were classified by three oral lesion experts and two senior dental hygiene students using the same rubric containing eight features. Classification agreement among and between raters were evaluated using Fleiss' and Cohen's Kappa. Classification agreement among the three experts ranged from identical (Fleiss' Kappa = 1) for "clinical action", to slight agreement for "border regularity" (Fleiss' Kappa = 0.136), with the majority of categories having fair to moderate agreement (Fleiss' Kappa = 0.332-0.545). Inclusion of the two student raters with the experts yielded fair to moderate overall classification agreement (Fleiss' Kappa = 0.224-0.554), with the exception of "morphology". The feature of clinical action could be accurately classified, while other anatomical features indirectly related to diagnosis had a lower classification consistency. The findings suggest that one oral lesion expert or two student raters can provide fairly consistent meta-information for selected categories of features implicated in the creation of image classification tasks in DiLearn.