Because a word's meaning has a way of haunting those who are ignorant of it. I recently came across the following:
“When adjusting for population, City X’s homicide rate was three times higher than City Y’s.”That’s redundant, and it indicates that the writer does not know what rate means. Rate in this context adjusts for population by definition, 8 per 100,000 or whatever. The most useful of several definitions of rate is this, from Merriam-Webster:
a : a quantity, amount, or degree of something measured per unit of something elseUse rate as if it meant simply quantity or number, and you may be taking part in the evolution of English. But for now, at least, you'll be using the word incorrectly — and driving me nuts.
© Peter Rozovsky 2012