Selecting questions for a challenge-response test

摘要

Methods, systems, and apparatus, including compute program products, for selecting a question for a challenge-response test. One of the methods includes obtaining question response pairs, wherein each question response pair includes a question about a first entity and a response to the question. Respective difficulty values for each question response pair are determined from a count of a number of times the question in the question response pair has been submitted as a search query to a search engine by users of the search engine. A request for a challenge-response test is received, wherein the request includes a context for the challenge-response test. Difficulty criteria for the challenge-response test are determined from the context. A first question response pair is selected that has a difficulty value that satisfies the difficulty criteria for the challenge-response test, the question from the first question response pair is provided in response to the request.

主权项

1. A computer-implemented method comprising:
obtaining a plurality of question response pairs, wherein each question response pair includes a respective question about a respective first entity and a respective response to the question that is an attribute value associated with the respective entity or a reference to a respective second entity that has a relationship to the first entity; determining a respective difficulty value for each question response pair from a count of a number of times the question in the question response pair has been submitted as a search query to a search engine by users of the search engine; receiving a request for a challenge-response test, wherein the request includes a context for the challenge-response test; determining difficulty criteria for the challenge-response test from the context; selecting a first question response pair that has a difficulty value that satisfies the difficulty criteria for the challenge-response test; and providing the question from the first question response pair in response to the request.