Value-added modeling (VAM), according to Daniel F. McCaffrey, Daniel Koretz, J. R. Lockwood, & Laura S. Hamilton (2006), offers the possibility of estimating the effects of teachers and schools on student performance.

If teachers are to be held accountable for the performance of their students, strategies for measuring the impact of their work must be refined or, at least, the uncertainties of these measurements must be taken into account ...

VAM is a collection of statistical techniques that uses multiple years of student test score data to estimate the effects of individual schools or teachers.

The idea of using VAM results to evaluate and reward administrators and teachers has been discussed in some school districts and political statehouses.

The recent literature on VAM suggests that teacher effects on student learning are large, accounting for a significant portion of the variability in growth, and that they persist for at least three to four years into the future.

Changes in the timing of tests, the weight given to alternative topics, or the methods used to create scores from students’ responses (the “scaling” of the test) could affect conclusions about the relative growth in achievement across classes of students. Such changes would, in turn, change estimates of teacher effects.

These and other researchers will delineate numerical differences among these differences in the next few years.

Then, hopefully, someone will go the next step to link teaching to the cost of a student learning to read the letter "a" when seeing /a/. Yeah!

And then, someone will study relative costs of using a live teacher and of using a Tablet PC or other mobile PC to learn the same processes and content.

I wonder where such progress will go next?

Tablet PC Education Blog