Wise heads in the office always used to discourage people from working with their friends. It'll be too distracting, if you promoted faster it could end a beautiful friendship and what about the complications if you end up in a relationship, they'd caution and worry.
Not any more. In fact, according to research published by the London School of Economics, making a conscious decision to place employees among hard-working friends can make them more productive at work.
But the key is the phrase "hard-working". Employees work harder when they work with friends who are more industrious than themselves, compared with when they work with people who are not their friends, a research paper, Social Incentives in the Workplace, has concluded.
Some of the old warnings may also not be too far off the mark, the study, published in the Review of Economic Studies, has concluded.
Employees were significantly less productive when they worked with friends who were less hardworking than themselves, it found.
The study looked at the productivity of fruit pickers and their networks of friends on a farm, with workers asked to name up to seven friends.
They were then observed on days when they worked alone to form an estimate of their average productivity and this was compared to their performance when they worked with friends.
One of the co-authors of the research, Professor Oriana Bandiera from the LSE, said: "Our research suggests that getting people to work with their friends could be one way for companies to motivate their workers without necessarily paying them more. However, this approach needs to be exercised with care since friends in the workplace can be a good or a bad influence."
According to the research, whether friends combined productivity was lesser or greater when they worked together or individually depended on their initial ability levels.
For example, an extremely slow friend could cancel out the good influence of a faster worker.
The overall effect on a company's performance of having friends work together depended on the balance of the workers' ability across the firm.
Report co-author Professor Iwan Barankay [crct], of the University of Pennsylvania, also said: "If most people in a company are slow, the friendship effect will actually slow down the few 'star' workers. If this is the case it would be better to have the hard workers work by themselves as opposed to with a friend."
An average worker was 10 per cent more productive when working with a friend who was more able than themselves.
By contrast, workers who were more able than their friends were 10 per cent less productive when they worked with their friends.
Because workers were paid a piece rate per kilogram of fruit picked, this corresponded to an increase or loss of earnings.
The researchers put their findings down to the desire of friends to socialise rather than being a side effect of friends cooperating to get the job done faster since fruit picking is individual work.
Co-author Professor Imran Rasul, University College London, added: "These fruit pickers work in rows. So if they go at the same speed as their friends they get to chat. If one is faster and shoots ahead, that's clearly not possible.
"Our research is also applicable to other types of work. If you are an administrator filling in forms, for example, the number of forms you complete will depend on how long you spend chatting to your colleague, and that will also affect your colleague's work rate," he added.
On the farm studied the researchers found that productivity would have only increased by 2.6 per cent if they had kept friends together at all times.
The authors also noted that this may not have led to an increase in profits if there was a cost related to reducing the flexibility of the workforce.