As more and more people “do their own research,” some end up consulting a website called PubMed. An argument I have encountered is that if a scientific paper is listed on PubMed, it must mean this is an all-around good and trustworthy paper. Alas, if only it were so simple...
PubMed can be thought of as the Google search engine of the life sciences. If I am looking for a published paper, if I am curious about a researcher’s publication record, if I want to see if a review of the evidence exists on a topic that has piqued my curiosity, my first stop is almost always PubMed. I was using it as a student; I kept on using it as a research assistant; and here I am, still using it as a science communicator. It is that useful.
PubMed is a way to query a database known as MEDLINE (and a number of secondary databases as well). MEDLINE is an inventory of publications that have to do with the life sciences and with biomedicine specifically, and it is administered at the National Institutes of Health of the United States of America. From 1971 to 1997, MEDLINE could only be accessed online through an institutional facility like a university. But in June of 1997, the search engine PubMed, which had been privately accessible for a year and a half, became available for free to the public. Anyone could access the PubMed website (after listening to their modem’s bloops and hisses) and search the vast database that was MEDLINE.
The breadth of knowledge available on this platform is staggering. One of the earliest papers I was able to find through PubMed dates back to 1781. It describes a new method for treating an abnormal opening into a tear duct. Apparently, two hundred and forty years ago, this was enough of a notable issue, and a surgeon by the name of William Blizard had something to say about it.
MEDLINE contains citations of articles from more than 5,200 academic journals, representing a total of 40 languages. In fact, the current front page of PubMed proudly announces that MEDLINE has as of now over 32 million citations. That’s more than 32 million academic publications on the life sciences alone and which are available at our fingertips. My crude estimate is that, if each publication was five pages long and we were to print them all and stack them, the pile would be 16 kilometres high. For a visual representation, that’s over 49 Eiffel towers high. The amount of research that has been published in the biomedical sciences is simply mind-boggling.
It should come as no surprise, then, that in this awkward pile-up of Eiffel towers (that would rise above where most commercial planes fly), there are more than a few stinkers. Indeed, if you search for “homeopathy” on PubMed, you will get (at the time of writing) 6,108 results. Homeopathy is an antiquated, pre-scientific philosophy based on sympathetic magic and stupefying dilutions that more often than not results in sugar pills devoid of pharmacological action. But if you think being listed on PubMed is an indication of legitimacy, you may be fooled into thinking that science recognizes the worth of homeopathy.
Andrew Wakefield’s fraudulent paper linking the measles-mumps-rubella vaccine to inflammation of the colon and to autism, and upon whose illusory foundation the modern anti-vaccine movement rests, is listed on PubMed (though it is marked as “retracted”). There is a journal called Medical Hypotheses whose articles are also discoverable through PubMed. The journal’s purpose is to publish theoretical papers, and its editors will consider “radical, speculative and non-mainstream scientific ideas” as long as they are written in a way that makes some kind of sense. One such paper proposes that ejaculation might be a potential treatment for a congested nose. Another argues that this handy intervention is “inconvenient, unreliable and potentially hazardous.” Both are, you guessed it, found on PubMed.
Then there is the issue of predatory journals. These are low-quality academic journals often set up for the sole purpose of making money. They will pretty much publish anything. Some of the papers published in these predatory journals are listed on PubMed.
Finally, even the non-fraudulent papers published by genuine journals and that report on actual scientific research should be approached with a level of skepticism. PubMed will list nutrition studies based solely on food questionnaires, where participants are asked to remember how many eggs they ate in the past month. PubMed will also list exploratory studies where the blood of participants was looked at from every possible molecular angle to see if something would turn up positive. And PubMed will list studies where an intervention was not compared to a control group. The results from all of these studies are bound to be questionable.
In science, reliability generally emerges from a body of evidence made up of rigorous studies that end up pointing in the same direction. So the next time someone sends you a far-fetched scientific paper and reassures you that it was on PubMed, you can reply, “So what?”
And if they ever complain of a stuffy nose, you’ll know which paper to send them. Hey, it’s listed on PubMed!
Take-home message:
-PubMed is a website that searches databases of life science publications like the MEDLINE database, which contains over 32 million publications
-PubMed lists good scientific papers, but also papers on fake sciences like homeopathy, fraudulent papers, radical hypotheses, and papers on low-quality studies
-Just because a paper can be found on PubMed does not mean it is a good scientific paper
