Most people don’t delete their profiles. They simply leave and never come back.
This means you need to make a good, honest, distinction between the number of members that have joined your community in it's lifetime and the number of members that are in your community.
You make this distinction by setting a boundary. A member that hasn’t participated in your community in the last 2 months probably isn’t a member. He might come back, but he’s not a member right now.
Most community managers don’t set this boundary. They cite their registered members as the number of members. It’s a badge of honour. But we both know it’s not true. It’s a deliberate mistake for one single reason: higher numbers make for better promotion.
Bigger numbers are more attractive. You’re more likely to hire me if I’ve managed a community of 100,000 members than 1,000 members. You're a culprit in this sham. The solution doesn’t begin with community builders/managers, it begins with clients asking two questions:
1) How many people joined your community?
2) How many have participated in the last 60 days?
Now you have a ratio. The number of members that participate after joining. You have a solid understanding of the community manager’s skill. Not only are you more likely to hire the better community manager, you’re more likely to hire an honest one.