It is possible to prepare an achievement test on which the scores have absolute meaning. For example, scores on a test of ability to add pairs of single-digit numbers can be used to estimate how many of the 100 addition facts an examinee knows. Or, if a test of word meanings is built by systematically sampling the words in a particular dictionary and systematically mixing words and definitions to produce test items, the test can be used to estimate what portion of the words in that dictionary an examinee understands, in one sense of that term.