Saturday, July 20, 2013

Bad Predictions

Megan McArdle has recently speculated that the GOP will have control of the government in 2017 based on a superficial reading of modern politics and gut instinct. The track record of pundits trusting their gut instincts instead of considering data driven and/or historical analyses is not good. Here is a part of McArdle's reasoning:
Since the Civil War, only two Democratic presidents have been succeeded by another Democrat.  Both of them–FDR and JFK–accomplished this by dying in office.

Since World War II, only four presidents have been succeeded by a member of their party.  As I mentioned above, two of them accomplished this by dying in office.  One of them accomplished this by resigning in disgrace ahead of his own impeachment.  Only one of them, Ronald Reagan, left office at the end of his appointed term and was succeeded by a duly elected member of his own party.  Mostly, the White House flips back and forth like a metronome.
Nate Silver has already demolished McArdle's claim at fivethirtyeight but his argument is statistical. My problem is with McArdle's scattershot history and logic. Noting that "Since the Civil War, only two Democrat presidents have been succeeded by another Democrat" ignores the many times the Republican party did successfully maintain control of the White House, which would itself undermine the whole "metronome" argument. While Democrats were not nearly so successful, that point obscures the massive party realignment that took place in the early 20th century. We might just as easily say that only once since the Civil War has the party that controlled the (white supremacist) solid South elected two different presidents sequentially, and that was Ronald Reagan and George H. W. Bush. What does that say about Republican chances in 2016?

The metronome-since-World War II argument is more interesting, but still far from convincing. "Only four presidents have been succeeded by a member of their own party" seems like quite a lot considering there have only been twelve presidents since World War II. And McArdle does not acknowledge extraordinary historical variables like, say, the Vietnam War and Watergate. Overall, the metronome argument fails to respond to the eras of party dominance that are characteristic of American history. Demographic groups brought together into party coalitions tend to have a good deal of inertia behind them. Black swan events and a preponderance of other electoral variations can produce a winning candidate whose party is not currently dominant, but that does not lend any credence to McArdle's metronome argument.

Looking to 2014, the Senate is the current worry for the Democrats. But 2016, despite McArdle's wishful thinking, looks much brighter considering the number of states the Republicans will have to defend. So a one-party government is possible, but highly unlikely in our future and certainly not with the likelihood McArdle suggests.

Incidentally, for those of you shocked and dismayed that Nate Silver is leaving The New York Times, have no fear. Sam Wang at the Princeton Election Consortium and Drew Linzer at Votamatic are both still right where they have been, and they are just as good (if not better) than Silver.

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