As output is hard to measure in most professional jobs, managers will fall back on the oldest gauge of performance: favouring those employees who get in early and leave late.

ECONOMIST: Business

Knowles has the Colgate smile, the ability to establish quick intimacy, and the attention to detail (touch a shoulder, make eye contact, gauge the back of the room) that a certain kind of pop star needs.

NEWYORKER: Show Runners

Captain Nasser Hussain is reportedly willing to gauge feeling among the cricket-viewing public back in England before making a final decision.

BBC: The back pages

It moves the steering wheel, using sonar to gauge distances, and offers the driver front and back video views.

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And, having watched in horror as the power gauge flashed a warning to me on my way back into London from the M25, "recharge anxiety" looks like it may be a recurring anxiety for electric motorists.

BBC: Electric cars: Charging ahead?

This trendline has been a great gauge for overall strength or weakness since the bull market started back in 1995.

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For the moment, the back-and-forth motion is occurring as the market continually tries to gauge how the European debt saga will play out.

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Portugal and Spain are also looking to the horizon to gauge how long and challenging it will be for both to tap back into the bond markets once this all blows over.

FORBES: Spain, Portugal And A Virtuous Circle Of Bailouts

The stock move was echoed by similar gyrations in other markets, where oil momentarily lost 0.7% before recovering, and the CBOE Market Volatility Index, the "fear gauge" known as the VIX, spiked 9% before falling back to its level just a few minutes earlier, down 5% on the day.

WSJ: Stocks Notch Strong Finish After Fake Tweet Sends Markets Reeling