What skill should standardized accountability tests emphasize?

We know the problems with assessment tests all too well: They encourage rote memorization of facts, employ outdated metrics, and compel educators to teach to the test rather than risk penalization should scores fall. Most alarmingly, although they focus on basic literacy and numeracy, these tests fail to appraise many of the skills critical for students in the twenty-first century, including creative thinking and problem solving across disciplines, teamwork, and technological literacy. Fortunately, educational organizations are developing solutions that move us past multiple-choice exams with too narrow a focus. Instead, these exams will ask students to use their knowledge in a variety of disciplines, testing them on what they understand, not simply what they've memorized. Students need many hands-on skills. Which one strikes you as particularly important to kids in the twenty-first century? We want to know.