This chapter examines the measurement of metacognitive judgments and compares six different measures of absolute accuracy and relative accuracy. A lively debate has centered on how to measure metacognitive judgments over the last two decades (Allwood, Jonsson, & Granhag, 2005; Dunn, 2004; Juslin, Olsson, & Winman, 1996; Keren, 1991; Nelson, 1996; Schraw, 1995; Stewart, Brown, & Chater, 2005; Wright, 1996). I take the position that different outcome measures provide different types of information that complement one another. While some outcome measures are better suited for specific research questions, it is not the case that one measure is best in all situations. I propose that it is essential to understand different types of judgment measures and to use them appropriately to pose and answer useful research questions.