This study examines whether the results of standardized tests are distorted when rewards and sanctions are attached to them, making them high-stakes tests. It measures the correlation in school-level test results -- including both score levels and year-to-year score changes -- on high-stakes and low-stakes tests administered in the same schools in nine school systems. It finds that test score levels generally correlate very well, while year-to-year score changes correlate very well in Florida but much more weakly in other school systems. It concludes that the stakes of high-stakes tests do not distort information about the general level at which students are performing, and in Florida they also do not prevent the tests from providing accurate information about school influence over student progress.