In a recent post on the Shanker Blog, researcher Matt Di Carlo chastises those “reformers” who expect transformational results from educational interventions.

“A recent report from the U.S. Department of Education presented a summary of three recent studies of the differences in the effectiveness of teaching provided advantaged and disadvantaged students (with the former defined in terms of value-added scores, and the latter in terms of subsidized lunch eligibility). The brief characterizes the results of these reports in an accessible manner – that the difference in estimated teaching effectiveness between advantaged and disadvantaged students varied quite widely between districts, but overall is about four percent of the achievement gap in reading and 2-3 percent in math.

“Some observers were not impressed. They wondered why so-called reformers are alienating teachers and hurting students in order to address a mere 2-4 percent improvement in the achievement gap.

“Just to be clear, the 2-4 percent figures describe the gap (and remember that it varies). Whether it can be narrowed or closed – e.g., by improving working conditions or offering incentives or some other means – is a separate issue. Nevertheless, let’s put aside all the substantive aspects surrounding these studies, and the issue of the distribution of teacher quality, and discuss this 2-4 percent thing, as it illustrates what I believe is the among the most important tensions underlying education policy today: Our collective failure to have a reasonable debate about expectations and the power of education policy.”

“Reformers” often boast about miraculous results but those results usually turn out to be the result of skimming, creaming, intensive test prep, or other kinds of manipulation of data. Real change is slow and incremental. Everyone know that but “reformers.”