Monday, November 15, 2010

Charters vs. Non-Charters in Newark

Bruce Baker. Associate Professor in the Graduate School of Education at Rutgers and blogger at SchoolFinance101, looks at performance in 4th and 8th grade math of charter schools versus traditional public schools in NJ. In "Searching for Superguy in Jersey" he’s created a statistical model for schools within urban centers and weighted achievement for free and reduced lunch rates, homelessness, rates, and student racial composition. His conclusion is fair and reasonable:
As you can see, there are plenty of charters and traditional public schools above the line, and below the line. The point here is by no means to bash charters. Rather, this is about being realistic about charters and more importantly realistic about the difficulty of truly overcoming the odds. It’s not easy and any respectable charter school leader or teacher and any respectable traditional public school leader or teacher will likely confirm that. It’s not about superguy. It’s about hard work and sustained support – be it for charters or for traditional public schools.
Dr. Baker’s scattergrams place both charters and non-charters at the high end of performance (“Beating the Odds”) and low end (“Underperforming”). He also features Newark-specific scattergrams. For example, the Newark scattergram for 8th grade math performance shows South Seventeenth Street Public School at the top of the heap. The DOE data (unweighted, by the way, unlike Bruce’s models) shows that the school, a pre-K through 8 school with 494 kids, has mixed results. In math, 40% failed the ASK5, 58% failed the ASK 6, 81% failed the ASK7 and 50% failed the ASK8.

Slightly below South Seventeenth on Dr. Baker’s scale, but still well above the “Beating the Odds” line, is North Star Academy Charter School, a K-8 school with 773 kids (and 1,775 kids on the waiting list). Here’s its math test results: 14.8% failed the ASK5, 9.7% failed the ASK6, 11.9% failed the ASK7, and 1.1% failed the ASK8.

The weighting formula is the only explanation for South Seventeenth’s superior slot on the scattergram. All the kids there (according to the DOE) are African-American; at North Star 85% are African-American and 15% are Hispanic. Almost all the students at South Seventeenth are listed as “Economically Disadvantaged,” depending on grade. At North Star most are. (Example: in 5th grade 114 out of 137 are listed as “Economically Disadvantaged.”)

Here’s one piece of the puzzle that Dr. Baker doesn’t address. Total comparative cost per pupil at South Seventeenth (and all Newark traditional public schools) is $19,305. Total comparative cost per pupil at North Star is $11,416. In other words, the non-charter spends almost twice as much per pupil as the charter. Now South Seventeenth has more special ed kids (16.8% are classified as opposed to only 7.8% at North Star) though all South Seventeenth’s are native English speakers and 14% of North Star kids’ first language is Spanish. Just trying to be fair.

In addition, the kids at South Seventeenth go to school for 180 days a year and each day is 6 hours and 20 minutes long. The kids at North Star go to school each year for 196 days and each day is 8 hours long, in spite of what must be daunting fiscal constraints. Class size is larger at North Star: 24.9 kids per class as opposed to 17.6 kids per class at South Seventeenth. If we’re trying to learn from charter schools, then it appears that, weighted values or not, longer school years and school days seems to matter and smaller class size doesn’t.


schoolfinance101 said...

Many false comparisons here.

1) the spending per pupil comparison is bogus in that it assumes that all NPS schools receive the district total per pupil. This ignores entirely the high concentrations of severe disability students in some schools, as well as the budgetary influence of other special schools. And it assumes that North Star spends only what is reported as is level of public support. Neither are true, but better data are currently unavailable. Working on that but NJ charter school financial reporting is sloppy at best - mostly just missing.

2) North Star achieves much of its high performance by systematic reduction of cohort members over time. NPS schools can't simply shed low performers from a cohort. See my previous posts.

3) North Star does not have that level (14%) limited English proficient students (source?). Rather, it's approximately 0% according to NJDOE enrollment data.

4) North Star has negligible special ed populations and many fewer low income kids.

So, even if we do find that North Star produces better value added than an NPS school (with lotteried in vs. lotteried out kids) - though the data are insufficient for doing so - we could not necessarily attribute the gains to school quality factors - because much would be a function of the selective cohorts/peer group. So, even if they are doing well, and could do well by even more students - that model hits a wall pretty fast. There aren't enough non-poor, non-special education, non-LEP kids in Newark to go around. And we can't just shed low performers (if that is what's happening with their dramatic cohort reduction from grade 6 to grade 8)

I would actually focus more interest on those charters that are a) serving more representative populations and b) retaining cohorts over time (TEAM, perhaps?). None are really serving special ed or ELL kids. But some are closer than others on other measures.

I noted on a previous post how Robert Treat would be hard to replicate - scale up. North Star is actually even more problematic in this regard, as far as I can tell.

NJ Left Behind said...

1) Actually, Bruce, I specifically mention the much higher rate of disabilities – and, thus, much higher costs – in traditional public schools. All my data comes from the DOE. Some peculiarities in the DOE data, certainly -- for example, some Newark non-charters report impossibly low rates of students classified as eligible for special education. Harriet Tubman reports only 5.2% of kids classified and Roberto Clemente says 6.8%.

2) I see that the size of North Star’s high school-level cohort is well below lower grades (which is why I only looked at 5th-8th grade output.) Not sure what to make of that, though I wouldn’t jump to the conclusion that they are purposefully “shedding low performers.”

3) Here’s the source for the 14% first language spoken at home:;d=7320;s=960;lt=N;st=T&datasection=all

4) Using the category “Economically Disadvantaged,” Northstar still has a substantial portion of kids from low-income homes (114 out of 137 in 5th grade, 96 out of 113 in 6th grade, 87 out of 108 in 7th grade, 75 out of 89 in 8th grade).

I’ll take a look at TEAM also. Scalability is obviously a big issue.