When I was a child, I fancied myself a great scientist. I would go around making "solutions" out of household and barnyard items. A little dish soap, a dash of pond water, fresh-cut grass and a few dead bugs shaken over horse manure and voila - some magical solution to achieve an unspecified agenda. Perhaps it was a cure for cancer or a new form of rocket fuel that would take men to Mars. Only time would tell. I would store the solutions in used pop bottles in our garage until someone found them and threw them away. You may say this ritual resembles witchcraft more than it does science, and you would be right. But, in my primitive mind I was emulating all of the key aspects of science - put things in a test tube (pop bottle) and swirl them around. I thought I was conducting good science because I was going through the motions of what I had observed on TV.
Hayek warned against making this mistake in this eloquent Nobel Prize Lecture, The Pretense of Knowledge. He was talking about economics, but I think his message can be applied more broadly. Don't assume the work you are doing or the study you are conducting is correct or meaningful because it mimics those you have seen before, and don't assume that the values you are measuring are pertinent because they are the ones you can measure. Be critical of others who have made this leap. Keep these considerations in mind and you will be able to guard yourself against much flimflam from economists, scientists, doctors, lawyers, mediums and experts of all kinds.