Since most jobs involve an ad-hoc mix of tasks some of which require total concentration and no interruptions it's far better to give people the option of working in a communal environment OR working somewhere quiet.

BBC: The pleasures and perils of the open-plan office

When Mr Arnold first looked into it, he says, what surprised him most was not so much the total size of the positions that the bank had taken as their high concentration.

ECONOMIST: British banking