1. A method for quantifying relevancy of a document to a training corpus, the method comprising: calculating, by a processor, an internal best match score for a relevant document relative to each training example in the training corpus by: determining cosine distances between the relevant document and training examples in the training corpus relative to term frequency-inverse document frequency weights associated with the training examples; determining the training example having a closest cosine distance to the relevant document; and outputting the training example having the closest cosine distance to the relevant document; wherein determining the training example having the closest cosine distance to the relevant document further comprises ranking the training examples by stretching the internal best match scores for the training examples linearly to cover a complete unit interval.