Rate and Ratio

[marion.royal@gsa.gov]

During one of Gunther's' presentations in Montreal, he was looking for a
replacement for the word rate to distinguish between
A. Rate as used in tax rate category
b. Rate as used  tax rate (percentage)
c. Rate as used in rate of speed

An alternative of "ratio" was offered, but I'm not sure this was resolved.
The problem may be that we habitually use incorrect terms, especially
within our domains.  I looked around a bit and noticed that in mathematics,
rate is used to compare two unlike units of measurement as in "kilometers
per hour" and ratio is used for comparison of numbers of the same units of
measure (gear ratio is 1:4).  The units of a ratio are typically not
expressed.

A currency exchange is a comparison of two different units, so currency
exchange rate would be accurate.

A percentage seems to me to be a ratio.  A tax of 10 percent would equate
to a ratio of 1 to 10 dollars.  Likewise with discounts.

Does this make sense to you?  Does it have a dramatic impact on business
vocabularies?



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