That’s the conclusion of one recent Australian study, anyway.

More than 70% of employees with Internet access spend some amount of the day on non-work activities, according to the research by the University of Melbourne. And those who waste time in moderation (for less than 20% of their total time in the office) are on average 9% more productive than those who use their computers for nothing but work.

Why is that? Because employees function better when they take short, frequent breaks, say the researchers who conducted the study. They often lose concentration and need to zone out for a few minutes to get it back.

Another possible factor: The most productive employees are the ones who have the time to surf the Internet.

Does this mean managers should let their employees waste all the time they want? Hardly, though many companies may be putting too much effort into enforcing a ban on personal computer use. Most experts recommend avoiding outright bans and instead addressing individual issues as specific performance problems.

1. Productivity drops and doesn’t go back up. There may be a transition period where telecommuters learn to be as productive at home as they were in the office. But if it lasts more than a few weeks, the arrangement is probably not the best fit.
2. They don’t answer messages. One caveat of letting employees work from home is often that they’re required to be available at all times during the work day to answer phone calls, IMs and e-mails. If the employee frequently won’t respond — and doesn’t have a good excuse — that’s a bad sign.
3. They respond, but it just doesn’t sound right. Crafty home-based slackers have started using computer programs (like this one) to hide the fact that they’re away from their desks. These applications let users create general, automatic responses to e-mails that come through their in-boxes.
4. Initiative goes out the window. It’s common for ambitious employees to become complacent once they’re no longer in the office all day. But home-based workers should still be expected to willingly take on new responsibilities and do more than just the bare minimum.