Wednesday, May 25, 2011

Conley and Dupor, revised

A couple posts back, on May 14 I criticized Timothy Conley and Bill Dupor for overstating their results in the abstract of a recent paper on the effect of the ARRA stimulus. The old abstract read:
Our benchmark results suggest that the ARRA created/saved approximately 450 thousand state and local government jobs and destroyed/forestalled roughly one million private sector jobs. State and local government jobs were saved because ARRA funds were largely used to offset state revenue shortfalls and Medicaid increases rather than boost private sector employment. The majority of destroyed/forestalled jobs were in growth industries including health, education, professional and business services.

On May 17, the authors posted a revision. The new abstract reads:
Our benchmark point estimates suggest the Act created/saved 450 thousand government-sector jobs and destroyed/forestalled one million private sector jobs. The large majority of destroyed/forestalled jobs are in a subset of the private service sector comprised of health, (private) education, professional and business services, which we term HELP services. There is appreciable estimation uncertainty associated with these point estimates. Specifically, a 90% confidence interval for government jobs gained is between approximately zero and 900 thousand and the counterpart for private HELP services jobs lost is 160 to 1378 thousand. In the goods-producing sector and the services not in our HELP subset, our point estimate jobs effects are, respectively, negligible and negative, and not statistically different from zero. However, our estimates are precise enough to state that we found no evidence of large positive private-sector job effects. Searching across alternative model specifications, the best-case scenario for an effectual ARRA has the Act creating/saving a (point estimate) net 659 thousand jobs, mainly in government. It appears that state and local government jobs were saved because ARRA funds were largely used to offset state revenue shortfalls and Medicaid increases (Fig. A) rather than directly boost private sector employment (e.g. Fig. B).
The new abstract is completely accurate, and does not overstate the paper's findings. I commend the authors for making the revision.

I would like to think that this represents a case of the blogosphere acting as a useful adjunct to the academic literature (and not just a case of me being a Statistics Nazi). The authors hopefully would have made a similar revision without any blog attention, but you never know.


  1. Apparently no one has anything to say when you say something nice!

  2. Anonymous5:32 PM

    so is Greg Mankiw going to link to the revised abstract as well...I wouldn't bet on it.

  3. Anonymous9:51 AM

    This "new" information was always in the paper. Authors leave these details out of the abstract to conform to submission guidelines at journals. Do you think you're more of a "statistics Nazi" than the authors? I doubt it.

  4. Anonymous11:31 AM

    ^Too funny. Offering nothing more than a juvenile snide remark about this blogger being a grad student, you claim that he should grow up. Part of being academically trained is to discuss papers, an activity that is actively encouraged by supervisors because it demonstrates serious interest and a matured willingness to engage the subject matter. The crucial part of the process is that others discuss and argue the content as well. But I suppose you would have him just lay about. He is just a grad student after all. The irony is lost on you.