The concept of testing for partial knowledge is considered with the concept of tailored testing. Following the special usage of latent trait theory, the word valdity is used to mean the correlation of a test with the construct the test measures. The concept of a method factor in the test is also considered as a part of the validity. The possible effect of scoring for partial knowledge on such hypothetical tests is considered together with the logic of these hypotheses. The application of latent trait theory to a mathematical model is used to provide estimates of the expected gain in information as a function of the increase in inter-item correlations. Finally, these concepts are combined with the concepts of tailored testing. Two aspects of tailored testing are considered, tailoring test length and tailoring test difficulty. The possibilities of adapting tailored testing to non-dichotomous item scoring are considered in order to adapt tailored testing to the use of partial knowledge in the test score. (CTM)