For the last 3 years, more than 80% of the respondents to the "Annual Phi Delta Kappa/Gallup Poll of the Public's Attitudes Toward the Public Schools" have stated that they would rather see a school's performance measure based upon "improvement shown by students" than the "percentage passing the test" (Rose & Gallup, 2007, p. 35). If this were to become the norm, the next question would be what "improvement" is significant? Educators need to understand "value-added" if they are going to use "improvement" to show that schools are improving student achievement. (Contains 4 figures.)