Welcome to this week’s clinical reasoning bias – “The Bandwagon effect”:
“the tendency to do (or believe) things because many other people do (or believe) the same”
Now I don’t even need to try and think of a clinical case to demonstrate this, as there as so many examples in the medical literature, but perhaps you could think of an occasion where this bias affects your own practice.
Let’s think about some of those examples over the years – and remember that the bandwagon effect occurs for doctors and for patients:
- The HERS study of 1998 suggesting exploring the relationship between HRT and breast cancer. How many women stopped their HRT based on a study that had limited external validity (i.e. didn’t exclude the confounder of women who smoked).
- The most recent media flurry of attention to LARCs and their unwanted side-effects.
- Fad diets – do we even need to go there?
- PSA testing – this one has upswings and downswings depending on the literature, attribution bias (if you’ve seen a prostate cancer picked up in an asymptomatic man via a PSA) and group think.
If you have the time or inclination, there is a fascinating article from 1925 exploring bandwagon bias. Dr Hutchison writes eloquently about the “Fashions and Fads in Medicine“. He describes a ‘fashion’ as an epidemic fad’ and describes some doctors influences as ‘faddists’ – who influence doctors of similar important to create a fashion. And nearly 100 years on, fashion and fads are still occurring, and faddists are now adept at social media influence, in fact they are actually tagged as influencers!
Here are some ‘historical‘ fads, just for a laugh because it’s the silly season:
1. Treatments for ‘disobedient children’ – bottles full of soothing syrup (65mg morphine/bottle)
2. Heroin-Hydrochloride to calm your cough
3. Erectile dysfunction treatment – electrical belt.
Yes, in the ‘old days’ research capabilities and processes were less robust than nowadays but doctors did understand physics, biochemistry and anatomy so surely they would understand that electric belts were not the answer? (Maybe they worked by scaring of the female partner and thus reducing psychogenic ED in the male). But doctors in the 1920’s didn’t have social media as we do. Social media is very influential in terms of group think. We have constant and immediate access to trends and norms but equally we have the opportunity to compare and moderate our practice against that of others. We can also moderate the ‘bandwagon effect’ through the use of evidence-based research – but there are still ‘faddists’ out there that we tend to listen to, as do our patients.
Now I know I said I would post a weekly clinical reasoning challenge, but it’s Christmas, and I’m about to start holidays and I’m tired. So the challenge for this week is to post an example of Bandwagon bias, and how we can mitigate for it. Feel free to place comments and engage in other’s posts on my Facebook page.
Wishing all a safe and relaxing holiday season, free of bias and clinical uncertainty….
Byrne, J. Skeptical Medicine. Cognitive Bioases. Retrieved from https://sites.google.com/site/skepticalmedicine//cognitive-biases
Cohen, L., & Rothschild, H. (1979). The Bandwagons of Medicine. Perspectives in Biology and Medicine, 22(4), 531-538.
Hutchison, R. (1925). Fashions and Fads in Medicine. Canadian Medical Association Journal, 15(11), 1170-1171.