Wednesday, January 12, 2011

The Ceiling Effect #2

Some blog followers might be interested in a recent post “The Ceiling Effect #2” [Hake (2011)]. The abstract reads:


ABSTRACT: Sheila Tobias (2010) in a recent APS News “Back Page” editorial “Teachers in the Crosshairs. . .”: wrote:

“In Houston, where a new value-added formula is being used to grade teachers’ skills, ‘N.Y. Times’ education writer Sam Dillon found a high school physics teacher out of the running for high bonuses because, as she reported, ‘My kids come in at a very high level of competence, scoring well before the semester begins.’ After she teaches them for a year, they continue to score well on a state science test but show less measurable ‘gain’ than other classes, so her bonus is small compared with those of other teachers. The teacher has invented a term of her own to characterize this distortion. She calls it the ‘ceiling effect.’ We might call it a saturation effect.”

It's unfortunate that the teacher’s bonus assigners were not aware that it’s the “average normalized gain” [g] = ([%post] – [%pre]) / (100% - [%pre]) [the square brackets [. . .] indicate class averages], often used in physics education research, that can (in some cases) be used as a gauge of relative course effectiveness, NOT the absolute average gain [G] = ([%post] – [%pre]).


To access the complete 11 kB post please click on .

Richard Hake, Emeritus Professor of Physics, Indiana University

Honorary Member, Curmudgeon Lodge of Deventer, The Netherlands

President, PEdants for Definitive Academic References which Recognize the Invention of the Internet (PEDARRII)>

REFERENCES [URL’s shortened by and accessed on 12 Jan 2010.]

Hake, R.R. 2011. “The Ceiling Effect #2” online on the OPEN! AERA-L archives at . Post of 12 Jan 2011 16:19:49-0800 to AERA-L and Net-Gold. The abstract and link to the complete post are being transmitted to various discussion lists.

Tobias, S. 2010. “Teachers in the Crosshairs: The Impact of ‘School Choice,’ ‘Reform,’ and ‘Accountability’,” APS News 20(1), January; online at .

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