I've heard several times that the existence of private or "charter" schools near public schools in the US harms public schools specifically because it draws "stronger"(grade-wise or socioeconomically) students away.
Allegedly having "stronger" peers somehow helps the educational process of the "weaker" students. And building private schools which "cream" (see explanation below) the better students will negatively affect the performance of the students who are left in the public schools.
For example, research by Coleman et al. (1966) shows that “the socioeconomic level of a student’s school had more effect on his achievement than any other measurable factor except the socioeconomic level of his home” (Jencks 1973,100).
From QUALITY, RACE, AND THE URBAN EDUCATION MARKETPLACE RECONSIDERED (page 273 (114 in pdf)) are based on this:
Coleman,J. S.,E. Q. Campbell,C. J. Hobson,J. McPartland,A. M. Mood,F. D.Weinfeld,and R. L. York. 1966. Equality of educational opportunity.Washington,DC: Government Printing Office.
Article which has some data but it's almost 50 years old and might be not that relevant.
I was wondering whether there's some (newer?) evidence (statistical or otherwise) to that claim being true (if true, how much effect does it have).
Given public school A that has some "strong" students, if some organization would open a private school B and those "strong" students would be accepted to school B and would be transferred there.
Would the remaining students in school A be affected by the absence of their "stronger" peers or not?
This could maybe checked by comparing public schools with similar population prior to school B's appearance.
When I'm talking about "creaming" I'm talking about the intentional and systematic use of selection criteria to choose which students attend a school (which is usually choosing the "better" students e.g better grades or better test results in some SAT-like test).