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Editor,—I read with interest the report by Mohan published in December.1 I agree that “Priorities for injury control have to be based on intelligent assessments of official statistics...”. This is what prompted me to call attention to the improper use of the word “rate” as presented in the second paragraph, where the author writes “....the rate in India (8.6) is....” in reference to table 1 “Distribution of deaths as a percentage of regional total”.
Rates and proportions (expressed as percentages) are different. A rate is the ratio of two different quantities (generally symbolised by the equation a/b) while a proportion is the result of dividing two quantities where the numerator forms part of the denominator (symbolised by the equation a/(a + b)). A proportion multiplied by 100 is a percentage.
Rates and proportions are not synonyms. It seems the author meant to say “percentage” and not “rate”. This mistake could confuse those beginning in the field of epidemiology, prompting them to think that “percentage” and “rate” are synonymous: they are not.