When you're having a work meeting, the more people that are invited the easier it is for the whole thing to get derailed, which is why every meeting needs a meeting "Police" to keep things on topic.
While everyone is assembled to talk about a big project that's being finished up this week, inevitably someone is going to decide that "Since we're all here…" it would be a good idea to bring up another project that's happening a few weeks from now, and by the way what's up with the coffee maker? Is it broken? And have you seen John's new puppy? Let's take a break in the conversation to look at pictures of it for 10 minutes.
A meeting "police officer" is exactly what it sounds like. The officer's job is make sure that the meeting stays on topic, and if it starts to stray speak up. He or she will also watch the clock and ensure that the meeting is moving according to its agenda.
That person shouldn't be the meeting organiser, and should have a copy of the meeting agenda, with what needs to be discussed and the amount of time that's allotted to each topic.
For instance, if your meeting is about a new ad campaign and you've plotted 15 minutes to talking about graphics and 10 minutes to talking about music, then after graphic's 15 minutes are up the officer will make sure everyone knows and push the meeting to move on to the next topic. If something off-topic comes up he or she can write it down to be addressed later.
The idea here is that the meeting organiser can sometimes be the one that keeps the discussion on one aspect of a topic going too long, so it's good to have another source in charge of timing. Also, if you have a lot to get through in a meeting, then allowing one aspect of it to run long (or giving up time for other topics like John's dog — I mean, have you seen it?!?) means that another has to run short.
The idea might seem (and might be) a bit off-putting at first, but if it's something your business implements regularly it can revolutionise your meetings. Knowing that you have 15 minutes and only 15 minutes to discuss something forces people to stay on topic and be efficient, and knowing that a meeting is going to both start and end on time makes everyone a little more willing to be a part of it.
An organised meeting that stays on topic will by in large be much more productive and offers the added bonus of you not having to schedule another one because you didn't have enough time to hit on everything in the first .