These panics are a useful barometer of economic confidence.
But without House leaders' telling members how to vote, such measures can often be a useful barometer of Congressional sentiment.
But these elections offer a useful barometer of political shifts.
The Brotherhood might thus be a useful barometer for gauging Egypt's political direction.
The push to raise the minimum wage is a useful political barometer: seven states have raised the minimum in just the last two years.
Straw polls can be useful barometers, but not of a candidate's actual popularity among actual voters.
"Rating agencies are useful barometers but they do not decide on France's policies," Fillon said.
But perhaps the banning of books is a useful barometer of prejudice.
Individual buildings can be useful barometers for measuring a changing cultural climate.
It's a useful barometer for us on what people think.