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Names and life choices: still more on the dentists named Dennis

After I posted again on the dentists named Dennis, commenter Donovan wrote:

The base rate given for the names Dennis, Jerry & Walter doesn’t pan out when you review the NPI Registry file maintained by the Centers for Medicare & Medicaid Services (CMS). The NPI Registry lists every health care provider in the US who bills for services. The frequency distribution of these three names in the NPI file is:
Dennis 4,442 47.42%
Jerry 2,423 25.87%
Walter 2,502 26.71%

If you run the same frequency distribution where the primary taxonomy is either 122300000X (generic code for dentist) or 1223G0001X (general practice dentist), here is what you get:
Dennis 556 48.06%
Jerry 291 25.15%
Walter 310 26.79%

So there is a tiny difference, but not impressively so. I [Donovan] declare the Dennis dentist myth busted!

I sent this to Brett Pelham, the author of the original study on names and life choices (Why Susie Sells Seashells by the Seashore: Implicit Egotism and Major Life Decisions). His response:

After a quick read of that comment, I [Pelham] am not sure I understand the critique, Is this person saying that the percentages for the three names for dentists are very similar to the percentages for all health care providers? If so, I’d suggest that it’s at least possible that this is because doctor also starts with D. At any rate, I do agree that the evidence we have for careers is methodoloigcally the weakest of all the evidence we have gotten over the years, and it’s easy to generate alternate explanations for some of the results.

I think we’ve gotten much stronger results for marriages. Also,since we published that first paper in 2002, we’ve done quite a few lab experiments that document the effect quite clearly devoid of any conceivable confounds. For example, people like a woman more than usual if she is wearing a jersey whose number was paired subliminally (below conscious threshold) with their own name in a 70 second conditioning procedure. Jerry Burger et al.(I think) have also done quite a few experiments that show that you’re more likely to help people whose (fake) first names are the same as your own.

I also reviewed a paper last month that used a much bigger data base than we found to look at doctors and lawyers. The paper showed (and I checked some of the data myself) that lawyers are more likely than doctors to have the surname “Lawyer” whereas doctors are more likely than lawyers to have the exact surname “Doctor.” I didn’t believe the names could be frequent enough to yield the effect until I repeated the part of the search myself that I could do for free.


  1. Daniel Lakeland says:

    As "The Thompson Twins" would have said…

    "Dr. Doctor, can't you see I'm burning…" with curiosity about how many people with last name "Doctor" or "Lawyer" there really are…

  2. Donovan says:

    I was just pointing out that if people named Dennis are more likely than Jerry or Walter to be dentists, then Dennis should represent a larger proportion of dentists' names than those of non-dentists. I suspect that the base rate estimates of the names Dennis, Jerry & Walter are currently inaccurate. As was stated in the original Pelham et al. article: "…the names Jerry and Walter have an average frequency of 0.416%, compared with a frequency of 0.415% for the name Dennis." However, this was supposed to be valid for 1990, almost 20 years ago.

    The NPI file contains any health care provider that bills for services, such as psychologists, optometrists, chiropractors, physical therapists, etc., so I doubt this could be attributed to a D for doctor effect (I myself do predictive modeling in Minnesota for a living). I would encourage Mr. Pelham to download this file and use it for further research in this area. It's free, and the quality of the data is quite good (it's just an incredibly large file).


    P.S., I regret to inform everyone that there are no dentists with the first name of Crentist. I leave it to future researchers to review the middle and last names for Crentist, Doctor or Toothpuller-Extraodinaire.