Such as? And more importantly, is there the slightest evidence that putting such monitoring in place actually helps increase output?

Almost no jobs are meaningfully measured in such a fashion because it penalizes thinking at the expense of spinning your wheels even when latter is far less or even negative in value if it wastes other employees time as well. It also fails to capture any relationship between input and output. If all you care about is butts in seats you can bill someone else for there productivity means nothing all you want is someone to take as long as possible to produce a level of output the client will pay for.