Reply #72: Here it is:

[LWolf]

From the 2003 Rand Corporation publication: "Charter School Operations and Performance: Evidence from California"

http://www.rand.org/publications/MR/MR1700/MR1700.ch9.pdf

STUDENT ACHIEVEMENT
One main objective of the legislation mandating charter schools is to
“improve student learning” (EC 47601). Although this objective seems straightforward, it can have two alternative interpretations:
(1) Charter schools should improve the learning of their pupils over
time and (2) charter schools should outperform conventional public
schools. If the objective is taken to mean that charter schools should
improve the learning of their pupils over time, then our conclusions
would suggest that most charter schools are meeting this objective,
because both charter and conventional public schools have experienced
growth in student performance in recent years. If the objective
is taken to mean that charter schools must outperform conventional
public schools, then the assessment leads to a different and
more complex set of conclusions. In our study, we evaluated the
performance of charter school students relative to conventional
school students because this was deemed the question of greatest interest
to policymakers. Our results suggest:

• Charter schools generally have comparable or slightly lower test
scores than conventional public schools after adjusting for the
ethnic and demographic characteristics of the students. However,
these effects vary across the different types of charter schools.
Our evaluation suggests that, controlling for student characteristics,
classroom-based conversion schools have comparable scores
in certain subjects or grade levels, in other cases higher scores, and
still in other cases lower scores. Classroom-based start-up schools
have higher test scores than conventional public schools across
grades and subjects except in elementary math, where the scores
are slightly lower. Finally, nonclassroom-based conversion and
start-up schools, relative to conventional public schools, have
lower test scores across the board.