2. The method of claim 1 , wherein the first feature score, the second feature score, and the merged feature score are of a plurality of possible values for each respective score, wherein the plurality of merging techniques comprise: (i) weighting the merged feature score based on the first feature score, (ii) weighting the merged feature score based on the second feature score, (iii) not considering the first feature score upon determining the first feature score does not exceed a minimum weight threshold for the first feature score, (iv) considering the first feature score upon determining the first feature score exceeds the minimum weight threshold for the first feature score, (v) not considering the second feature score upon determining the second feature score does not exceed a minimum weight threshold for the second feature score, and (vi) considering the second feature score upon determining the second feature score exceed the minimum weight threshold for the second feature score, wherein computing the first feature score merges the first set of features of the plurality of items of evidence, wherein computing the second feature score merges the second set of features of the plurality of items of evidence, wherein the plurality of features comprise: (i) a quality, (ii) a relevance, (iii) a sentiment, and (iv) a source of each candidate answer and each item of evidence, wherein computing the second feature score for a first item of evidence of the plurality of items of evidence based on the first feature score of the first item of evidence comprises: not considering the first feature score of the first item of evidence when computing the second feature score for the first item of evidence upon determining that the first feature score of the first item of evidence does not exceed the minimum weight threshold for the first feature score; and weighting the second feature score of the first item of evidence based on the first feature score of the first item of evidence upon determining that the first feature score of the first item of evidence exceeds the minimum weight threshold for the first feature score.
2. The method of claim 1 , wherein the first feature score, the second feature score, and the merged feature score are of a plurality of possible values for each respective score, wherein the plurality of merging techniques comprise: (i) weighting the merged feature score based on the first feature score, (ii) weighting the merged feature score based on the second feature score, (iii) not considering the first feature score upon determining the first feature score does not exceed a minimum weight threshold for the first feature score, (iv) considering the first feature score upon determining the first feature score exceeds the minimum weight threshold for the first feature score, (v) not considering the second feature score upon determining the second feature score does not exceed a minimum weight threshold for the second feature score, and (vi) considering the second feature score upon determining the second feature score exceed the minimum weight threshold for the second feature score, wherein computing the first feature score merges the first set of features of the plurality of items of evidence, wherein computing the second feature score merges the second set of features of the plurality of items of evidence, wherein the plurality of features comprise: (i) a quality, (ii) a relevance, (iii) a sentiment, and (iv) a source of each candidate answer and each item of evidence, wherein computing the second feature score for a first item of evidence of the plurality of items of evidence based on the first feature score of the first item of evidence comprises: not considering the first feature score of the first item of evidence when computing the second feature score for the first item of evidence upon determining that the first feature score of the first item of evidence does not exceed the minimum weight threshold for the first feature score; and weighting the second feature score of the first item of evidence based on the first feature score of the first item of evidence upon determining that the first feature score of the first item of evidence exceeds the minimum weight threshold for the first feature score. 3. The method of claim 2 , wherein the first merging technique comprises a combination of at least two of the plurality of merging techniques, the method further comprising: computing a merged feature score of each of the plurality of candidate answers based on the first merging technique, wherein the merged feature scores of the plurality of candidate answers are used to select one of the plurality of candidate answers as a correct response to a question presented to the question answering system.