Misconception 2: Value-added scores are inaccurate because they are based on poorly designed tests. Most standardized tests are indeed flawed, but this is not a problem created or worsened by value-added.Is that correct?
Seven Misconceptions About Value-Added Measures
by Douglas N. Harris
Harvard Education Letter - March|April 2011
As I understand it, New York's state tests can't be used for value-added purposes. The tests are shorter in some years, longer in others, and somehow don't correspond to a one-year measurement of learning. Or so we were told. Certainly they don't provide any sense of where a child might be within a year's worth of content. New York tests are scored 1 to 4, so if your child scores a middling 3, what does that mean on a scale of 10 months? Nobody knows.
I had been assuming that in order to use a standardized test as a value-added measurement, the tests had to be normed month-by-month as the Iowa Test of Basic Skills is normed:
Grade Equivalent (GE)When your child takes the ITBS from one year to the next, it's simple to see whether he's made a year's progress in a year's time. If, at the end of grade 3, he scored a 3.10 on computation (grade 3, month 10), he should score a 4.10 on computation at the end of 4th grade.
The grade equivalent is a number that describes a student's location on an achievement continuum. The continuum is a number line that describes the lowest level of knowledge or skill on one end (lowest numbers) and the highest level of development on the other end (highest numbers). The GE is a decimal number that describes performance in terms of grade level and months. For example, if a sixth-grade student obtains a GE of 8.4 on the Vocabulary test, his score is like the one a typical student finishing the fourth month of eighth grade would likely get on the Vocabulary test. The GE of a given raw score on any test indicates the grade level at which the typical student makes this raw score. The digits to the left of the decimal point represent the grade and those to the right represent the month within that grade.
But how would you make that determination using the New York tests?
Or is there some other comparison you make from year to year?