Of the O'Callaghans whose literacy was recorded, 82.8% could both read and write, 2.9% could read but not write, and 14.2% could do neither. The figures were much the same for men and women. Bear in mind these figures include young children; the census itself only counted people aged nine and over when calculating illiteracy, on the grounds that it was unfair to label a child illiterate before they'd had a chance to learn.