Suddenly everyone wants to do a “deep dive” into every subject. Today, for instance, Pew offers a “Deep Dive into Party Affiliation.” The phrase appears in The Ridiculous Business Jargon Dictionary right after “decruit,” an Orwellian term for firing someone. I would have said that metaphorical uses of “deep diving” were much less common even a year ago, but these things are hard to measure. Books always provide a lagging indicator and don’t necessarily catch up with spoken language even after a delay. But the Google book trend for the phrase “deep dive” is interesting. It shows a rapid increase in the 1970s, a bear market for deep diving in the 1980s-1990s (my impressionable years), and then a steep upward slope until 2008, which is the last year of available data.

To decode the scale: this graph means that one of every five million phrases in printed books in 1972 was the phrase “deep dive.” Some uses probably referred to pearl fishers and Soviet submarines. But the increase could reflect an emerging business metaphor.

The word “cliché” was invented by French printers in the age of moveable type to refer to a precast word or phrase that could be dropped into text for efficiency. I don’t think you would bother to forge a cliché for the word “deep dive” as long as it stayed at the level shown above. Thus it isn’t literally a cliché. But two parts in every ten million seems like plenty to me.