As most people have already figured out, open-plan offices are the dumbest management fad of all time, because (according to a Harvard study) they destroy productivity and reduce rather than increase collaboration.

The reason? Open-plan offices prevent you from doing many things that are essential to a healthy, creative, and communicative workplace. Specifically, in an open-plan office you can't:

1. Concentrate without distractions.

Collaboration is meaningless unless individuals are able to get their individual projects (or parts of projects) done completely. Even clerical work requires concentration; creative work even more so. Open-plan offices are noisy, both audibly and visually (which is why headphones don't completely work). Work is always subject to interruptions, intentional and otherwise.

2. Have a private conversation.

In an open-plan office, anything you say is likely to be overheard. This makes it difficult or impossible to talk about anything that might be private, misconstrued, or contrary to management interests if it became public knowledge. You can't discuss half-baked ideas or sensitive issues, have a personal discussion, or organize a union without "big brother" and all his little siblings listening in.

3. Have an animated conversation without annoying everyone.

Collaboration is supposed to help workers become excited and engaged. In open-plan offices, however, employees know they're bothering other people when their conversations get too enthusiastic. So they tone their voices down, which dampens the energy.

4. Create a personalized environment.

People feel more positive about work when they can create their own little "home away from home." With open-plan offices, you might have your coffee mug and a family photo, but that's about it. Otherwise, you're stuck with whatever schlocky hotel-lobby-esque corporate decor some architect thought would look cool.

5. Escape the office *sshole.

Almost every workplace has one or more individuals who are just plain obnoxious--compulsive flirts, energy vampires, and so forth. A private office--or even a cubicle--creates a territorial barrier that allows you to keep your distance. In an open-plan office, you can move but you can't hide.

6. Take a power nap.

It's a well-documented fact that napping makes people more creative. Taking a nap, however, is virtually impossible in an open-plan office, not just because of the noise but because you never know when somebody might come up behind you and nudge your chair. With a private office, you can close the door and take a few z's in quiet safety.

7. Avoid airborne germs.

Flu spreads easily enough in traditional office environments. In an open-plan office, a single sneeze guarantees that every surface within a radius of 25 feet for so will be covered with bacteria or viruses. Private offices (and even cubicles) tend to limit the spread of airborne sickness.

8. Control the room temperature.

Open-plan offices are set to a single average temperature, usually one that's comfortable for a medium-size man wearing a suit, which is several degrees too cold for most women. Private offices often have individual temperature controls. If not, they can be cooled by blocking the heating vent or warmed with a space heater.

9. Avoid being ogled.

Open-plan offices expose everyone to constant observation. Because women are more frequently judged on their appearance than men, open-plan forces women to be overly aware of what they're wearing and consciously cognizant that, for some men, they're part of the scenery.

10. Have a phone conversation on a weak line.

Listening to half a conversation is more distracting than listening to both sides, because you mind automatically fills in the other side of the conversation. That's why when people make calls in an open-plan office, they try to keep their voices low. But if you have a lousy connection and must speak up, everyone suffers.

11. Use a speakerphone without driving everyone else nuts.

In a private office, a small group can teleconference with third parties without creating noise pollution for everyone working on that floor. With open-plan offices, you have to find a conference room that hasn't already been staked out by people trying to find a little privacy. 

12. Have some private time.

Introverts (roughly a third of the population) find the presence of other people physically and emotionally draining. To recharge, they need to be alone, but that's impossible without leaving the office, unless you count hiding in a bathroom stall. Introverts tend to be more creative and innovative than extroverts, so making them unproductive is foolish and short-sighted.

Just to be clear: Going back to cubicles is not the answer. Cubicles are just open-plan offices with higher barriers; they're almost as bad. Here's what really works: private offices surrounding a hub of common area that's specifically for socializing.

That's how Pixar arranges its offices and how Apple used to have things set up before it drank the Kool-Aid and built its spaceship. Hey, ever notice that innovation at Apple seems to have come to a screeching halt since the move? Wanna guess why?