Yes, it does. Children in the poor, working class and middle-class districts in our high-cost counties significantly underperform their peers elsewhere. In the six high-cost California counties, statistically only forty percent of 8th graders in a middle-class district are predicted to meet or exceed their English Language Arts standards, compared with 50% of children in districts in the average-cost counties -- that’s 10% more of the student population and thousands of children in Oakland (Alameda County), San Francisco, West Contra Costa, San Rafael and San Jose.  In Math, it’s a fall from 38% down to 32%.

These differences grow as you go down the socioeconomic scale -- and, surprisingly, do not disappear at the top end -- though the parcel taxes, education foundation grants, and PTA donations prevalent in most of the wealthiest districts do narrow the gap -- making the contrast within counties between rich and poor even starker:

Explanation and Sources:  It is hard to evaluate the assertion that test scores indicated that any regional cost deficit in the high-cost districts are, somehow, made up to students either by the environment in which they were raised or external funding.  However, CEPA at Stanford (the Center for Educational Policy Analysis) publishes datasets for its analyses. Sean Reardon published a dataset he used in a New York Times article last year that includes Socio-Economic Status for 500+ school districts in California.  That is downloadable from CEPAs website, then can be cross-indexed from the NCES identifiers to the California school district codes with the district file from the CDE.  Finally, it is easy to download the latest Math and ELA test scores (% Meet or Exceed Standard) from Ed-Data.org.  

To illustrate, here are the breakpoint characteristics, with income in 2010 dollars, as detailed in Reardon’s white paper on status, race and academic achievement: