Posts Tagged ‘preferences’

a model for policy making

November 3, 2008

US elections, statistics, internet

key takeaways:

  • single dimension of political mapping. in the US 1 axis is enough to map the political system.
  • Duverger’s Law – effective number of candidates is district number + 1 = 2 in US. that is why there is just a 2 candidates per territory. this explains 2 party per district, but why 2 all across.
  • internet as new media – people expose themselves more to what they believe rather than plurality. so there is polarization.


policy making:

a spatial model on policy making, single dimension:


  • actors have preferences on the spectrum. when they take action, they do it purely on how far they are away from an ideal point.
  • the median voter ideal point is mapped on the spectrum
  • another point on the spectrum is the status quo
  • assume one chamber, majority role, median voter tilts majority.
  • every bill will move towards the median voter position
  • president has veto, his ideal vote is p, can be over-ridden by member O, 66th on the spectrum
  • any movement away from president beyond O, will be vetoed. if the distance from O to bill is less then O to status-quo, veto will be overturned.
  • the median voter is the agenda setter and they determine how the bill will be proposed
  • introduce: filibuster: 40th most and 60th most conservative member. (because of Cloture). so bill has to be between point 40 and 60.

so have the following points. P president, F1and F2 for filibusters, Sq, status quo, C for median voter. B, the bill has to be, between F1 and F2 and extend to O66 (or O33) towards the president.

during election the following change, P, potentially dramatically, and some movement in points of congress (initally assume no change). still F1 and F2, change. if obama takes, P swings from right to left, F1 does not change much as democrats will not lose a lot of sits in the senate, and F2 will move considerably to towards left. F2 will actually move from republican to democrat.

so changes will change according, new SQ range. depends on P and F60 (which relates).


now spectrum can be changes according to public opinion, (desire to be re-elected), money and power

surprisingly, one dimension predicts very well. liberal vs conservative.

there is more delegation to president re foreign policy

gary cox has some books on strategic voting