This chapter chronicles ETS research and development contributions related to the use of constructed-response item formats. 1 The use of constructed responses in testing dates back to imperial China, where tests were used in the selection of civil servants. However, in the United States, the multiple-choice format became dominant during the twentieth century, following its invention and use by the SAT ® examinations created by the College Board in 1926. When ETS was created in 1947, post-secondary admissions testing was largely based on tests consisting of multiplechoice items. However, from the start, there were two camps at ETS: those who believed that multiple-choice tests were sufficiently adequate for the purpose of assessing "verbal" skills and those who believed that "direct" forms of assessment requiring written responses had a role to play. For constructed-response formats to regain a foothold in American education several hurdles would need to be overcome. Research at ETS was instrumental in overcoming those hurdles.The first hurdle was that of reliability, specifically the perennial issue of low interrater agreement, which plagued the acceptance of constructed-response formats for most of the twentieth century. The second hurdle was broadening the conception of validity to encompass more than predictive considerations, a process that began with the introduction of construct validity by Cronbach and Meehl (1955). Samuel Messick at ETS played a crucial role in this process by making construct validity relevant to educational tests. An inflexion point in the process of reincorporating constructed-response formats more widely in educational tests was marked 1 Constructed responses to a prompt or question can range in scope and complexity. Perhaps the most common constructed response is the written essay. However, short written responses to questions are also considered to be constructed, as are spoken answers in response to a prompt, mathematical responses (equations, plotted functions, etc.), computer programs, and graphical responses such as architectural designs.