The received wisdom in the proposal profession – reflected in the APMP Foundation examination – is that one should use ‘serif’ fonts (such as Times New Roman) for body text, and a ‘sans serif’ font (such as Arial) for headings and captions. Having played with a few typefaces over the years – including some interesting experiments, setting out the same proposal in different fonts and gathering feedback from users – it’s always seemed like a fairly sensible guide.
So, I decided recently to look for the underlying evidence to support the two sides of the debate. That took me to a fascinating article by Alex Poole, entitled “Which Are More Legible: Serif or Sans Serif Typefaces?”. Alex explains that “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.”
He talks through various typographical definitions in detail, then “reviews the evidence for and against the legibility of serif and sans serif typefaces”, drawing extensively on various academic studies of the issue. And his 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. 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. 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.
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.