[speedgibson] Speed Gibson: I Had No Idea - Part 5

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Posted by Speed Gibson:
I Had No Idea - Part 5
http://speedgibson.powerblogs.com/posts/1197255945.shtml


   If you're still with me, having read parts [1]one, [2]two, [3]three,
   and [4]four, you now know as I do how complicated our K-12 funding
   formulas really are. Allow me to illustrate further, revisting the
   Transportation Sparsity Revenue calculation.
   I re-worked the provided example for the mythical "Gopherville" public
   school district, only the numbers didn't tie out. Here's what the
   "Financing Education in Minnesota 2007-08" booklet said:

     Transportation Sparsity Revenue per Pupil Unit = [(formula
     allowance x .1469) x (the logarithm of the district's sparsity
     index and .26) x (the logarithm of the district's density index and
     .13)] - (forumula allowance x .0485).
   = [($5,074 x .1469) x (the log of .2 and .26) x (the log of .09 and
       .13)] - ($5,074 x .0485).
       = [$745 x .658063 x .731226] - $246
       = $358 - $246
       = $112

     Total Transportation Sparsity Revenue = Revenue per Pupil x Pupil
     Units
   = $112 x 1,000
       = $112,000

   Previously, I simply noted that logarithms of fractions like this are
   negative, but I should have checked further. The numbers don't compute
   as shown. Could they have meant natural (base e) logarithms? Did ".2
   and .26" not mean their sum, .46? Nothing worked, so I looked up the
   underlying statue 124C.10, sub-division 18:

     Pupil transportation sparsity and safety revenue allowance.
     (a) A district's transportation sparsity allowance equals the
     greater of zero or the result of the following computation:
     (i) Multiply the formula allowance according to subdivision 2, by
     .1469.
     (ii) Multiply the result in clause (i) by the district's sparsity
     index raised to the 26/100 power.
     (iii) Multiply the result in clause (ii) by the district's density
     index raised to the 13/100 power.
     (iv) Multiply the formula allowance according to subdivision 2, by
     .0485.
     (v) Subtract the result in clause (iv) from the result in clause
     (iii).
     (b) Transportation sparsity revenue is equal to the transportation
     sparsity allowance times the adjusted marginal cost pupil units.

   Do you see any logarithms here? True, the exact mathematical
   formulation of .46 to th 26/100 power is exp(.26 x ln (.46)), but on a
   spreadsheet, it's typically just .46^.26. For once, the law is more
   clear than the interpretation, one provided by Minnesota House of
   Representatives' Department of Fiscal Analysis.
   Let me say that again. An agency of our Legislature cannot interpret
   the laws being passed. I dare say that a sizable majority of our 201
   Legislators couldn't follow it either. It was the creation of policy
   wonks with too much time of their hands.
   Doing a little more spreadsheet analysis also suggests that the final
   aid amount calculated is actually fairly linear vs an inferred number
   of student-miles. I submit that simply paying the districts the IRS
   standard mileage (48.5 cents per mile in 2007) times the student-miles
   actually driven is about the same as this wild formula. Actually, it
   pays the districts a little more, and I'm sure they wouldn't turn it
   down.
   The best news for you the reader may be that this is the final part of
   this particular series! But as The Drudge Report says, "developing..."

References

   1. http://speedgibson.powerblogs.com/posts/1196921233.shtml
   2. http://speedgibson.powerblogs.com/posts/1196952124.shtml
   3. http://speedgibson.powerblogs.com/posts/1196986085.shtml
   4. http://speedgibson.powerblogs.com/posts/1197149139.shtml