A computer-implemented method for displaying reduced data sets based on pre-classification of a larger data set in a user interface, comprising: receiving a plurality of activity records describing a plurality of activities associated with the user; grouping the plurality of activities into one or more pre-classified data sets based on the plurality of activity records; providing the user with a summary (102, 103, 104) of a pre-classified data set of the one or more pre-classified data sets via a user interface; providing the user, via the user interface, with a user interface element that is configured to allow the user to categorize all activities in the pre-classified data set together based on the summary; receiving input from the user via the user interface, wherein the input assigns a category to all activities in the pre-classified data set together based on the summary, wherein grouping the plurality of activities into the one or more pre-classified data sets based on the plurality of activity records comprises: using a predictive model to determine a predicted category of each of the plurality of activities, wherein the plurality of activity records are provided as input to the predictive model; grouping the plurality of activities into the one or more pre-classified data sets based on the predicted category of each of the plurality of activities; and training the predictive model using historical activity records associated with categories to predict a category based on an activity record and the user's confirmation or denial of a predicted category of one of the plurality of activities as an active feedback for the predictive model. receiving a plurality of activity records describing a plurality of activities associated with the user; grouping the plurality of activities into one or more pre-classified data sets based on the plurality of activity records; providing the user with a summary (102, 103, 104) of a pre-classified data set of the one or more pre-classified data sets via a user interface; providing the user, via the user interface, with a user interface element that is configured to allow the user to categorize all activities in the pre-classified data set together based on the summary; receiving input from the user via the user interface, wherein the input assigns a category to all activities in the pre-classified data set together based on the summary, wherein grouping the plurality of activities into the one or more pre-classified data sets based on the plurality of activity records comprises: using a predictive model to determine a predicted category of each of the plurality of activities, wherein the plurality of activity records are provided as input to the predictive model; grouping the plurality of activities into the one or more pre-classified data sets based on the predicted category of each of the plurality of activities; and training the predictive model using historical activity records associated with categories to predict a category based on an activity record and the user's confirmation or denial of a predicted category of one of the plurality of activities as an active feedback for the predictive model. using a predictive model to determine a predicted category of each of the plurality of activities, wherein the plurality of activity records are provided as input to the predictive model; grouping the plurality of activities into the one or more pre-classified data sets based on the predicted category of each of the plurality of activities; and training the predictive model using historical activity records associated with categories to predict a category based on an activity record and the user's confirmation or denial of a predicted category of one of the plurality of activities as an active feedback for the predictive model.