Achievement tests play an important role in modern societies. They are used to evaluate schools, to assign students to tracks within schools, and to identify weaknesses in student knowledge. The GED is used to grant the status of high school graduate to anyone who passes the test. Recipients currently account for twelve percent of all high school credentials issued each year in the United States. But do achievement tests predict success in life? With The Myth of Achievement Tests, James J. Heckman, John Eric Humphries, Tim Kautz, and a group of scholars explore how the GED came to be used throughout the United States and why our reliance on it is dangerous. Drawing on decades of research, they show that, while GED recipients score as well on achievement tests as high school graduates who do not enroll in college, high school graduates vastly outperform GED recipients in terms of their earnings, employment opportunities, educational attainment, and health. The differences in success are driven by character skills like conscientiousness, perseverance, sociability, and curiosity that achievement tests like the GED do not adequately capture. Not only are these skills important in predicting a variety of life outcomes, they can be measured and they can be taught. Using the GED as a case study, the authors explore what achievement tests miss and call for a return to an emphasis on character in our schools, our systems of accountability, and our national dialogue.