This research provides lengthy proof of a principle of social science known as Campbell's law: "The more any quantitative social indicator is used for social decision-making, the more subject it will be to corruption pressures and the more apt it will be to distort and corrupt the social processes it is intended to monitor." Applying this principle, this study finds that the over-reliance on high-stakes testing has serious negative repercussions that are present at every level of the public school system. Evidence of Campbell's law at work was found in hundreds of news stories across America, and almost all were written in the last few years. In addition to news stories, traditional research studies, and stories told by educators about the effects of high-stakes testing are also part of the data. The data fell into 10 categories. Taken together these data reveal a striking picture of the corrupting effects of high-stakes testing: (1) Administrator and Teacher Cheating; (2) Student Cheating; (3) Exclusion of Low-Performance Students From Testing; (4) Misrepresentation of Student Dropouts; (5) Teaching to the Test; (6) Narrowing the Curriculum; (7) Conflicting Accountability Ratings; (8) Questions about the Meaning of Proficiency; (9) Declining Teacher Morale; and (10) Score Reporting Errors. (Contains 10 tables and 115 notes.) [For Executive Summary, see ED508510.]