[tokenadult]

Regarding "if you seem to have done everything correctly", I don't think that any honest scientist can claim that his/her study had no limitation or flaw.

Hear. Hear. This, of course, was the thrust of Richard Feynman's famous Caltech commencement speech on "Cargo Cult Science."

http://www.lhup.edu/~DSIMANEK/cargocul.htm (adapted HTML text)

http://calteches.library.caltech.edu/51/2/CargoCult.pdf (PDF version as published by Caltech)

As Feynman said, "The first principle is that you must not fool yourself--and you are the easiest person to fool. So you have to be very careful about that."