Typeface Legibility

A meta-analysis, published as an open-access book in 2022 under the title The Legibility of Serif and Sans Serif Typefaces: Reading from Paper and Reading from Screens, looked at existing literature regarding the relative legibility of different typefaces as presented in different mediums.

Times New Roman is a typeface, while a font is a specific treatment of a typeface, like “Times New Roman, size 14, bold.”

Some typefaces (including Times New Roman) have little lines on their endpoints, and these lines are called serifs. A serif typeface has serifs, a sans-serif typeface (like Arial) does not.

There are other, in-between typeface styles that straddle the line between serif and san-serif, but the primary dichotomy in the English-language typeface world is between faces with serifs and those without.

There’s a common belief, based mostly on anecdote, but also a bit of older research, that serif typefaces are easier to read because their shapes are more legible, and possibly because the serifs help guide the eye from one character to the next.

It’s also commonly believed that serifed faces are usually more legible in smaller sizes and on paper, while sans-serifs are more ideal for screens, like phones and laptops.

This meta-analysis found, however, that the majority of existing work in this space demonstrates no difference in legibility between these two typeface categories, and that the research which does seem to show differences between them usually suffer from methodological issues.

It also found that previous research that seems to both hold up and which had no major methodological flaws actually indicated that the big difference in terms of legibility and intelligibility is not between serif and sans-serif categories, but between individual typefaces, some of which are just a lot more readable than others (and this seems to be true across all mediums).

In other words, some typefaces have difficult to read lower-case a’s, some have better (in the sense of being easier to parse in different contexts) upper-case D’s, and so on.

Rather than supporting the assertion that serif or sans-serif typefaces will tend to be better on paper or screens for legibility and intelligibility purposes, then, the existing research actually says that there are more and less legible, intelligible faces in both categories. People who design websites and books should thus use both types if they want to, while avoiding faces with confusing, similar-looking letters when possible (and adjusting the spacing, not the typeface, if they’re optimizing for people with visual impairment or dyslexia).