This paper discusses issues related to the design and psychometric work for mixed-format tests --tests containing both multiple-choice (MC) and constructed-response (CR) items. The issues of validity, fairness, reliability and score consistency can be addressed but for mixed-format tests there are many decisions to be made and no examination or examination program faces exactly the same choices. This paper raised some issues and used the AP experience to illustrate the types of questions that need to be addressed and outlined the strong test development processes that need to be in place to address the issues.