Bloomberg Survey of Law Professors Hides Self-Selection Bias
A story published Friday by Bloomberg News surveyed constitutional
law experts around the country and found that the overwhelming majority
of respondents believe the Supreme Court has no proper grounds on which
to strike down the mandate portion of the Affordable Care Act. Not
mentioned in the Bloomberg story is the fact that nearly half of the
respondents have made campaign donations to President Obama.
The fate of the President's signature achievement, the Affordable
Care Act, will be
announced this week by the Supreme Court. That decision is widely seen
as playing a role
in the President's reelection chances this fall. In advance of the
ruling, Bloomberg News emailed surveys to 131 professors at 12 law
schools. An overwhelming majority of respondents, 19 of 21, believed the
individual mandate should be upheld based on legal precedent, but only 8
of 21 believed that would happen. The obvious conclusion? Politics was
affecting the Supreme Court:
There was broad agreement that the ruling, barely four
months before November’s presidential election, has the
potential to hurt the Supreme Court’s reputation as an impartial
Eighteen of the 21 professors said the court’s credibility
will be damaged if the insurance requirement -- which passed
Congress without a single Republican vote -- is ruled
unconstitutional by a 5-4 majority of justices appointed by
The Bloomberg News piece has been widely circulated, especially on the
left, where blogs have pointed to it as proof that the Affordable Care
Act would survive if not for the influence of politics. Sites like Daily
Kos and Balloon Juice were joined by James Fallows of The Atlantic who cited the Bloomberg piece to support his contention that the U.S. was undergoing a "coup."
But a closer look at the Bloomberg survey reveals a serious problem.
Of the 131 law professors contacted, only 21 chose to respond, about 16
percent. Digging into the public donations records for the individuals
who responded reveals a fairly clear case of self-selection bias.
Nine of the 21 respondents, 43 percent, have donated to the Obama
campaign. But even those who haven't donated to a particular party have
identifiable political views. For instance, Professor Anne Joseph O'Connell has offered advice to the Obama administration in the form of this Center for American Progress report. For those not familiar with it, CAP is a progressive think tank known of its close ties to the White House and for funding the progressive blog Think Progress. Professor Richard Parker is one of the founders of Mother Jones magazine and describes himself as a progressive.
It should go without saying that we can't assume a particular
partisan identification affects an individual's legal judgment in a
given case. Then again, this is precisely the assumption these
professors seem to be making with regard to the Supreme Court's
conservative Justices and the ACA. A look at the chart above may suggest a reason
for their jaundiced views. Bloomberg News should have mentioned these connections to better inform readers that the opinions were not those of disinterested observers. Ironically, these professors may have made
the case that interpretation of the law is too often colored by politics, just not in the way they intended.