1. A computer-implemented method, comprising: receiving documents responsive to a query, each document having a respective associated score indicative of the document's relevance to the query, wherein: each respective associated score is based on a respective value for each of a plurality of different score factors; each score factor for a given associated score corresponds to a different criterion than each other score factor for the given associated score; and each score factor has a respective trustworthiness score that indicates a respective reliability of values determined based on the score factor; determining, based on the trustworthiness scores for the score factors of a plurality of the associated scores of a plurality of different documents, a value-based distribution of the trustworthiness scores for each of the different score factors of the plurality of associated scores along a dimension based on relative values of the trustworthiness scores, the distribution including trustworthiness scores for multiple score factors for each of the different documents; adjusting the value of at least one score factor of a given associated score by an amount that is determined based on: a relative position of the at least one score factor's respective trustworthiness score in the distribution with respect to other trustworthiness scores in the distribution; and a measure of how widely the trustworthiness scores for each of the different score factors of the plurality of associated scores are distributed in the distribution; adjusting the given associated score based on the adjusted value of the at least one score factor; and ranking the documents to account for the adjusted associated score.