6. The method of claim 5 , wherein processing, by the data processing system, the input question using the identified QA system pipeline to generate one or more candidate answers for the input question comprises: merging the separate ranked listings of candidate answers into a single ranked listing of candidate answers; and presenting the single ranked listing of candidate answers to a user via a user interface.
5. The method of claim 4 , wherein processing, by the data processing system, the input question using the identified QA system pipeline to generate one or more candidate answers for the input question comprises generating, by each of the QA system pipelines associated with matching clusters in the plurality of clusters, a separate ranked listing of candidate answers.