Introduction Why You Need a Book Like This PART ONE: PRINCIPLES OF DATA INTERPRETATION, OR, HOW TO KEEP FROM GETTING STATISTICALLY SNOOKERED Beware of Averages Follow the Money Beware of the Uncritical Acceptance of Convenient Conclusions Watch for Selectivity in the Data Show Me the Data! Beware of Nostalgia Beware of Causal Explanations from Correlational Data Be Aware of Whether or Not the Statistics Used Are Numbers or Rates (Percentages) Know Whether You're Dealing with Ranks or Scores Make Sure That the Statistic Used Is the Right One Ask How the Variable Is Defined Ask How the Variable Is Defined, and Then Ask What the Criterion Measure Is Differentiate Practical and Statistical Significance Look for Trends, Not Snapshots Beware of Trends Ask What the Consequences Are Even if the Interpretation of the Data Is True Beware of Changing Demographics Try to 'See Through' Graphs Beware of Big (Small) Numbers Beware of Generalizations PART TWO: ASPECTS OF ACHIEVEMENT The Rise of Testing Types of Tests Other Indicators of Achievement PART THREE: HANDLING THE TOUGH QUESTIONS How Come American Students Fall Farther behind Their International Peers the Longer They Stay in School? Why Are Test Scores Falling? How Come Private Schools Do So Much Better Than Public Schools? Why Don't We Have Vouchers So That the Money Could Follow the Child? Why Don't We Use Charter Schools as Laboratories for Innovation for the Rest of the System? Why Are We Throwing Money at the Schools? Why Are SAT Scores Still Falling? Why Don't Bright People Go into Teaching? With All the Talk about Standards and Accountability, Why Aren't Teachers and Principals Held Accountable?