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What is the difference between "bring in" and "bring on" in terms of employment?

Example sentences:

The company president wanted to bring on an efficiency consultant.

The company brought in a new team of project planners.
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If you mean "recruit" then the usual term is "bring in". "bring on board" is also a standard idiom (sounds a bit jargony).

"bring on" doesn't sound right to me in this meaning. As applied to employees, "bring on" to me would mean "encourage/develop the career of".
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Like Mr Wordy, I'd say it's either bring in or bring ... on board. bring in may be temporary or permanent. bring ... on board is only permanent.

The company president wanted to bring in an efficiency consultant.

The company brought in a new team of project planners.
The company brought twelve new employees on board this year.

CJ