We discuss instances where correlation does not imply causality a great deal at Chez Badmom.
A year ago,
Sandra Tsing Loh asked me to write up my observations comparing Iris' school 3 blocks east of us to the school she would have attended if we had bought a house 3 blocks west of us. It's a bit late, but she's not paying or grading me.
(I've noted previously that
I am not a stranger to late assignments.)
It helps if you read what
she has to say about school statistics.
http://greatschools.net is the easy-to-use, test-driven school listings resource visited by one in three U.S. K-12 families (30 million users). While the compilation of data is incredible, greatschools.net has an unfortunate “one number” rating system, based (essentially) on a school’s API score as averaged over the entire student body. This number which correlates most strongly with homogeneous populations of affluent families and high real estate values (in the same way SAT scores are strongly linked with family income). Parents tend to wrongly conclude they must move to an expensive suburb (where starter homes are $1.2 million) to find quality teachers for their children.
As luck would have it, the 2008 average home prices in
90266 and
90278 (as estimated by ESRI) are $1,188,703 and $845,655. Don't faint. Our neighborhood is still a bit rough around the edges and some people won't even visit it after dark. LA is just plain expensive.
Let's call the school in the expensive suburb school A. Greatschools.net gives it a 10 (out of 10) rating and school B, Iris' school, gets an 8. The
academic performance index or API, is another one number school summary. The two schools receive 943 and 885 respectively.
Which peer group would you like to buy for your kids? (You are not buying an outcome, only a peer group.) The one with the higher achieving kids? Before you shell out $1.2 million for a shack near school A, take a closer look at the numbers.
| School A | School B |
| zip code | 90266 | 90278 |
| median income | $141,734 | $87,447 |
| avg SFR price | $1,188,703 | $845,655 |
| Greatschools rank | 10 | 8 |
|
| CA API 2008 | 943 | 885 |
|
Parent Educ %
|
|
|
| HS dropout | 0 | 5 |
| HS grad | 2 | 13 |
| some college | 7 | 23 |
| college grad | 36 | 39 |
| postgrad | 51 | 21 |
|
| CST Math, Kids with Postgrad Parents |
Grade 2
| 453.2 | 448.3 |
| Grade 3 | 452.2 | 478.2 |
| Grade 4 | 430.6 | 451.0 |
| Grade 5 | 439.2 | *
|
|
|
|
* No comparison can be made for 5th graders because the sample size at school B is too small.
More than half the parents in school A hold graduate degrees. If you compare apples to apples, and only the kids whose parents hold graduate degrees, the results are flipped. The kids in school B have higher Math test scores. (Which is not the same as saying they are better at Math, but that is a subject better left for another time.)
I am posting details for only the Math scores because the English scores don't show such a strong pattern. Kids at school A score slightly better in English, but I suspect it is because no students in school A are English learners. The average English scores for grades 2-4 are 412 and 409 respectively.
3 points is in the noise, but a math gap of 26 points is significant.
The difference is even more striking if you know that school B allows any child who will turn 5 before the December 2 cutoff date to enroll in Kindergarten. School A requires that any child born in the Spring, Summer or Fall be evaluated for 'Kindergarten readiness'. Kids in school district A are a half year older than kids in school district B. (One September birthday child from school district A attends school B because the principal insisted she repeat Kindergarten until she gained more reading fluency!) Kids in district A are also more likely to have attended academic preschools, have hired tutors and a quiet place to study.
If you rely solely upon Greatschools.net, you will never learn this stuff. Go visit your neighborhood schools. Talk to some kids, parents and teachers about what they like and don't like about their school.
I am not advocating that you try to enroll your kid in school B. Instead of chasing high test scores, I believe that concerned parents should channel their energy into helping to raise the quality of their neighborhood school. And you can't do that if you are killing yourself working around the clock to afford the most expensive neighborhoods.