The Word Nerd has received a few requests to explain the difference between these two words. They are often used incorrectly by very intelligent people. A recent op-ed piece by Niall Ferguson (The Fragile Empire) in the Vancouver Sun is one such example. Mr. Ferguson writes, “The most recent and familiar example of precipitous decline is the collapse of the Soviet Union.” Mr. Ferguson, who is a professor at Harvard, does, of course, mean the “precipitated decline.”
Precipitous is an adjective that means dangerously steep or like a precipice.
Precipitate is a verb that means to hasten the occurant of or cause to occur prematurely. My Canadian Oxford dictionary also gives this definition: send rapidly into a certain state or condition. This final definition is exactly what Mr. Ferguson means in his op-ed.
One of the Word Nerd’s colleagues e-mailed her with this handy little sentence to help you remember which word to use: “A wee dram might precipitate a fall from a precipitous mountain.”
I must take issue with your reasoning on three counts.
First, there is nothing at all wrong with “precipitous decline,” as the decline in question has been demonstrably steep. Second, “precipitous” is usually confused with “precipitate” in its adjectival form (with the a pronounced as a schwa, unlike the verb), which means “headlong, hurried, hasty, rash” (OED).
Third, your proposed correction — “precipitated decline” — is both unnecessary and outright wrong, as the verb makes no sense without referring to the precipitating agent.