Absolutely true. A team of JHU researchers was able to separate the effect of education from the effects of family and environment. They found that while all socio-economic groups progressed more or less evenly on academic performance measures throughout the academic years - the low socio-economic status students stayed the same or slightly regressed during summer vacations, whereas the scores of higher socio economic status kids improved during the vacation period. Thus, they were able to attribute the disparity in academic performance at the end of schooling to the influence of family and environment, ratheer than schools. To my knowledge, their results were even quoted in WSJ.
That, however, goes against the conservative mantra and teacher bashing, not to mention organized religion's lust to get their bloody hands to public education coffers.
wojtek