Needed: A Lot of Good Men

We have seen that “economically disadvantaged” (“ED”) students generally underperform their more affluent peers (“Not ED”) on the SOL tests. 

The natural consequence of that is that divisions with more ED students generally deliver lower pass rates.  Less obviously, as the percentage of ED students increases, the pass rates of the Not ED students decrease while those of the ED students are only slightly lowered.  For instance:

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There is a lot of scatter in those data.  Indeed, the only robust correlation is in the all-student division average rates, where the effect of increasing numbers of ED students is to be expected.

Looking for other factors that might have more predictive effect, let’s turn to the census data showing numbers of “female householder, no husband present” families in the Virginia jurisdictions.  The latest data there are for 2017.

To start, here are the division average pass rates on the 2017 reading tests v. the no-husband percentages:

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Notes: The census data do not include Colonial Beach and West Point, both of which have independent school districts; their census data probably are subsumed in reports for the counties that include those towns.  The gold square on the graph is Richmond; the red diamonds are the peer cities, from the left Newport News, Hampton, and Norfolk; the green is Charles City; purple, Lynchburg.

Whew!  This is much more dramatic: The ED graph (2018 data) has a slope of –2.8 % per 10% increase in the Ed population.  Here (2017 data) we see a slope of nearly -6.4% for a 10% increase in the no-husband population.  The fitted line of the ED SOL graph extrapolates to a pass rate of 63.3% at 100% ED; the no-husband graph extrapolates to a pass rate of 25.7 at 100% no-husband households.

For a look at the divisions with a tougher job, here is the no-husband graph with only the high percentage divisions shown (the fitted line is for the entire dataset).

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The math data tell much the same story.

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Take a bow, ghost of Secretary Moynihan.

Taking a further step, here are the reading data broken out for the ED and the Not ED students.

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The ED data extrapolate to 29.8% at 100% no-husband households; the Not ED extrapolation gives 50.2%.

Looking just at the >25% no-husband divisions:

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Note: The second graph is too busy as it is so I’ve left the labels off the ED series.  You can identify the points there by looking for the labeled Not ED points directly above (i.e., same % no-husband).

Recalling that correlation does not imply causation, we cannot say that the missing husbands are the cause of these effects.  We can say that both ED and Not ED pass rates are generally lower in divisions with larger percentages of female parent homes and that the effect is nearly the same for both ED and Not ED students.  As well, the absence of the husband predicts over a fifth of the variance (statistic-speak for scatter from the fitted line).

Richmond, as usual, is underperforming. 

(Darn!  Another excuse that’s available to RPS only if they’re willing to lie.)

The math data sing a variation on the same theme.

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We can draw at least two conclusions:

  1. As with the ED population, the relationship of SOL test results to the number of no-husband households shows that the raw SOL pass rate is a defective standard for measuring division academic performance.  Said more succinctly: The SOL measure punishes a division for poverty and, still more powerfully, for single parenthood in its student base.
  2. Even with the pass rates corrected for effects of the large ED and no-husband populations, Richmond schools underperform.  Atrociously.