Have you ever been halfway through a meeting and thought to yourself, "What is this meeting about and why am I here?" If so, you are not alone. Too many of us rush from meeting to meeting without the time to reorient ourselves. This is a problem that can be easily solved by starting EVERY meeting with the 3 Ps: Purpose, Product and People.
Start the meeting by saying, "The purpose of this meeting is to discuss ______. At the conclusion, we will have this product (ie. a new process, program, procedure or progress). You are here because of your expertise in______, and/or Jane will report on the ______. We will need you to ______ for this meeting to be a success."
This will take a few minutes at the beginning of the meeting. But, it ensures that everyone there can start with the context needed to have a successful experience. Imagine how much more effective your meetings would be when everybody is on the same page. There will be no lag as people try to figure out where they are and what they need to contribute.
What should you do if you are not leading the meeting? I recommend that you ask the meeting leader to restate the purpose of the meeting and what the product will be if the meeting is successful. Most meeting leaders will agree to the request. I guarantee that you are not the only person who needs that information. If you do this on a regular basis you can "retrain" your meeting leaders to provide the important information when opening a meeting.
By the way, end 5 minutes early. That allows your participants to get to their next meeting on time. Everyone will thank you for that!