Logical fallacy/Appeal to authority

A logical fallacy in which a person presenting a position on a subject mentions an authority who also holds that position, but may not be an authority in that area. For instance, the statement "Arthur C. Clarke recently released a report showing it necessary to floss three times daily" would be unlikely to impress many people, as Arthur C. Clarke is likely not an expert on [dental hygeine]?. Much of advertising relies on this logical fallacy, as well as on the /Bandwagon fallacy.

Citing a person who is a recognized authority in the field is likely to carry more weight, and deservedly so. But this is still strictly speaking a logical fallacy, especially when the question itself is a matter of opinion or a question of some controversy. While experts are less likely to be mistaken than others, it is not impossible or even uncommon.