To estimate this, you simply take a randomized sample of people irregardless of their preferences and have half of them act one way and half act the other way. There are a bunch of other methods. In many cases, there's no reason to believe there are any unique differences between the majority and the minority.
To name some examples:
Professors still most rely on the lecture format even though active learning is more effective.
About half of all college students bring laptops to class at least some of the time even though hand written notes are generally more effective. Granted, a lot of these students aren't using their laptop to take notes.
Most men buy dress shoes with glued on soles and top-grain leather even though full-grain leather welted shoes will last 5-10 times as long for 2-3 times the price and often less than that. A good $200 shoe brand is a much better value than most of the $130 shoe brands.
Most companies still conduct interviews when hiring employees; unstructured interviews to boot if the person hiring isn't from HR, but the best evidence suggests interviews are mostly useless.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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