[RyanZAG]

We should probably keep doing studies to check how dentists think we should brush our teeth. We just shouldn't have dentists do a study on a variable that directly harms their income as we would already know the results they would give before the study is even done.

If you wanted a study on that variable, you'd likely need to at least get input from someone who says going to dentists is a bad idea - but at that point, you're just going to have a shouting match and a statistics measuring contest between the dentists and the guy who doesn't think anybody should see dentists. Your results would likely be contradictory and fairly useless.

We haven't yet found a way to do such studies in a useful manner, and it's an ongoing problem in politics that has yet to have a solution. And may never have a solution. And it's very important to be able to determine when such study variables align with the financial and ideological requirements of the researcher.

If you can tell without doubt what the result of a study by a certain group will be before the study takes place, it's usually a red flag.

[pryce]

I think your examples make your conclusions less likely, not more.

* Dentists, in particular, would secure more work if they organised and actively promoted dental practices that they knew were harmful. Nevertheless, that doesn't occur.

* Doctors as a group, similarly might stand to benefit from drawing out a disease for longer. Despite this, it is an absurd and baseless claim to make of doctors as a group, though presumably some unethical individuals might on occasion. An individual from a different year my medical school was recently charged with murder; this doesn't have me in a crisis over the legitimacy of the profession.

I note however it is a valid and compelling argument to make against pharmaceutical companies -which do have a theoretical financial incentive to pursue non-curative remedies over curative ones (guiding research priorities, and/or attempts to lessen the cost of production of known curative remedies), and this is followed by multiple documented examples showing this occurring in practice.

Among clinicians actually having to face sick people in person, this behaviour seems to be extremely rare.

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Regarding your specific example about "asking dentists how often to brush your teeth", there is in fact quite a healthy debate between dentist organizations and medical organisations - the former arguing that 3x per day is best for dental health, while (some) medical organizations argue that 2x per day is a better balance between dental health specifically, versus the added risk to general health of harmful bacteria entering the bloodstream from minor cuts on gums caused by brushing. In that debate, it is instructive to note that neither dentists nor doctors organisations accuse the other of acting in bad faith. In this instance, asking dentists as a group how often to brush your teeth is actually a quite sound idea, and the idea that they provide self-serving answers is comically absurd; if anything their current published guidelines on this question is too good for your dental health, at (very slight possibility) the expense of your general health.

For a more in-depth discussion of research and abuses of research on questions of health, I heartily recommend "Bad Science" (2008) by Ben Goldacre. One chapter is available free online here [1].

[1] https://www.badscience.net/2009/04/matthias-rath-steal-this-...