Poole does a thorough job in this article of describing and evaluating the viewpoints, including references and links to various analyses. He summarizes his findings in the introduction (good!) and the conclusion.
My long-held belief, uh, preference: serif faces in body copy and sans serif faces in headlines and headings. But I now believe that my preference was based mostly on what I was used to from my study in journalism and my work in the newspaper business. My belief now is that the "what I was used to" influence I had is also what influences the preferences of many people. And that preference is hard to substantiate scientifically.
I tend to favor sans serif faces now in most uses (especially for reading on computer monitors)--but not any sans serif face (and not any serif face in my past preference). Each typeface must be considered for legibility ... and aesthetics. What face creates or supports the mood or tone of the document you're producing?
Poole writes in the introduction (emphasis added):
An argument has been raging for decades within the scientific and typographic communities on what seems a very insignificant issue: Do serifs contribute to the legibility of typefaces, and by definition, are sans serif typefaces less legible? To date, no one has managed to provide a conclusive answer to this issue.And his thoughtful conclusion:
What initially seemed a neat dichotomous question of serif versus sans serif has resulted in a body of research consisting of weak claims and counter-claims, and study after study with findings of “no difference”. Is it the case that more than one hundred years of research has been marred by repeated methodological flaws, or are serifs simply a typographical “red herring”?
It is of course possible that serifs or the lack of them have an effect on legibility, but it is very likely that they are so peripheral to the reading process that this effect is not even worth measuring (Lund, 1999).
Indeed, a greater difference in legibility can easily be found within members of the same type family than between a serif and a sans serif typeface. (Tinker, 1963, Zachrisson, 1965). There are also other factors such as x-height, counter size, letter spacing and stroke width which are more significant for legibility than the presence or absence of serifs. Poulton, 1972; Reynolds, 1979)
Finally, we should accept that most reasonably designed typefaces in mainstream use will be equally legible, and that it makes much more sense to argue in favour of serif or sans serif typefaces on aesthetic grounds than on the question of legibility. (Bernard, 2001; Tinker, 1963)_______
Poole's article is featured today, Feb. 3, in my daily online paper, Garbl's Plain English Paragraphs, available at the Plain Language tab above and by free email subscription.