1. A computer implemented method for identifying, based at least in part on a machine learning (ML) model, candidate values to provide to a question answering (QA) system as part of a case, the method comprising: receiving a case, wherein the case includes a plurality of documents for evaluation by the QA system; evaluating the plurality of documents using natural language processing (NLP) to identify one or more concepts reflected by text content within the plurality of documents in the case, wherein the text content within the plurality of documents includes a first distinct value and a second distinct value of a plurality of distinct values for at least a first one of the concepts, wherein one or more of the plurality of distinct values includes a respective collection of one or more attributes; computing by the machine learning (ML) model executing on a processor, a respective confidence score for each of the plurality of distinct values, wherein the ML model comprises a logistical regression model built to compute the scores to select concept values based on a plurality of training cases, wherein each training case provides a plurality of documents and an indication of a preferred value for each concept having multiple values, wherein the preferred value for each concept is determined by: assigning a weight to each of the one or more attributes, wherein the one or more attributes include: (i) a date of an observation in the training case, (ii) a decisiveness of language used for the observation, and (iii) an accuracy of a procedure undertaken to make the observation; determining whether the one or more attributes meets a previously established relevancy threshold, and i) if the relevancy threshold is met, correlating, based on the assigned weights, a predictive quality of the one or more attributes in relation to a respective concept value to determine the preferred value and ii) if the relevancy threshold is not met, foregoing correlating, based on the assigned weights, a predictive quality of the one or more attribute in relation to a respective concept value to determine the preferred value; and selecting, based on the respective confidence scores, the first distinct value of the plurality of distinct values as a candidate value for the first concept to provide to the deep QA system to process the case; prior to submitting the case to the QA system, returning at least the candidate value selected for the first concept to present in a user interface; and submitting the case to the QA system using at least one selected value.