The phrase "efforts used" is correct and usable in written English.
You can use it to refer to the attempts that were made in order to complete a task or achieve a particular goal. For example, "Our team put in a lot of effort and we are proud of the efforts used to complete the project."
Earlier efforts used air to cool the metal, but this air cuts efficiency.
Efforts used to centre on chivvying known supporters to the polls.
But all of the early efforts used technology that relied on a fast-spinning disk with perforations to pass light.
Senator John Cornyn of Texas, who leads the G.O.P.'s Senate campaign efforts, used Facebook to urge his colleagues to slow the bill down.
There was insufficient attention to investigating and disrupting the activities of perpetrators compared with efforts used to "contain" behaviour of the girls.
For the past year, I've been working with the faculty and research institutes at NYU's Robert F. Wagner Graduate School of Public Service to integrate and enhance the social media efforts used to promote its events, programmes and publications.
The first efforts, using chest X-rays, were disappointing.
SIR - We applaud your efforts to support the use of rigorous evaluations of poverty-alleviation efforts using randomised trials (Economics focus, June 14th).
Unfortunately, there's no easy way to help humans learn from the experience of other drivers (although there have been some interesting efforts using virtual reality).
According to Tizen Experts, the South Korean company is now focusing its efforts using the platform on two entry-level devices for emerging markets.
In many parts of the province, the militant group Lashkar-e-Taiba is taking part in rescue efforts, using its own boats and ambulances.
