A cohort analysis mechanism analyzes cohorts with similar attributes to extrapolate additional knowledge and answer a question in a question answering system. The cohort analysis mechanism identifies cohorts for an entity of the question and extracts relevant data concerning the cohorts. The cohort analysis mechanism aggregates the relevant information for evidence scoring and answer scoring to answer a question posed to the question answering system. The aggregating of the data includes combining and ranking answers from the cohorts, gathering evidence and then answering the question with the gathered evidence.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. An apparatus comprising: at least one processor; a memory coupled to the at least one processor; a cohort analysis mechanism residing in the memory and executed by the at least one processor that analyzes cohorts with similar attributes to answer a question input to the cohort analysis mechanism by aggregating data from the cohorts to gather statistically significant evidence to answer the question, and wherein the cohorts are entities with similar characteristics to an entity of the question and available in a corpus of data. 2. The apparatus of claim 1 wherein the cohort analysis mechanism aggregates data from the cohorts to gather statistically significant evidence by extracting answers, evidence and confidence from the cohorts for the question and ranking answers from the cohorts. 3. The apparatus of claim 2 wherein the cohort analysis mechanism uses the ranked answers to gather statistically significant evidence of the cohorts to answer the question. 4. The apparatus of claim 1 wherein the cohort analysis mechanism is part of a question answering application that answers a natural language question. 5. The apparatus of claim 1 wherein the question is a medical question for a patient and the cohort analysis mechanism processes the medical history of the patient and finds the cohorts from medical histories of other patients to predict an answer from the cohorts. 6. The apparatus of claim 3 wherein the cohort analysis mechanism uses the ranked answers to gather statistically significant evidence of the cohorts to answer the question and wherein the cohort analysis mechanism determines an answer to the question using evidence gathered from a set of cohorts where case attributes in the set of cohorts does not exactly match attributes of the question. 7. The apparatus of claim 6 wherein the question is a medical question for a patient and the cohort analysis mechanism processes the medical history of the patient and finds the cohorts from medical histories of other patients to predict an answer from the cohorts. 8. The apparatus of claim 3 wherein the cohort analysis mechanism combines the answer from the cohorts with answers using conventional question answering in an answer scoring block of a conventional question answering system to answer the question. 9-15. (canceled)