Examining the Onscreen Legibility of the Number '0' and '1'

This article reports on the features that influence the legibility of the numbers ‘0’ and ‘1’ using classification tree analysis. These numbers were reported to be two of the most confused characters in a larger study examining the legibility of lowercase letters, digits, and symbols across 20 different typefaces. Classification tree results suggested that the most influential feature for the ‘0’ was height, and the most influential feature for ‘1’ was perimeter. These results can be used to help typographers design characters that optimize legibility. Optimal legibility for onscreen numbers is important in situations that include reading online identifiers, such as user names and passwords, or deciphering alphanumeric codes onscreen, such as air traffic control.