"And day by day, attending the temple together and breaking bread in their homes." (Acts 2:46)
There are seasons in a church when the most striking thing is that nobody leaves. The service ends and people simply stay, standing in the aisles, in the lobby, in the parking lot, talking about things that matter, until the building finally has to be closed. That is a metric no one counts. No one puts lingering on a report. There is no line on any form for how long people stood in a cold parking lot because they did not want the evening to end, and yet it may be the single most honest indicator of whether God is doing something.
Because you cannot fake it. You can fake attendance. You can fake enthusiasm for the length of a song. You cannot make grown adults with jobs and children stand around in the cold for an hour and a half talking about the Lord. They only do that when something happened.
So here is a question for your church, and for every church. When the service ends, how fast does the room empty? A room that clears in four minutes has been well-run and largely untouched. A room that will not clear has met with God, and the people in it are reluctant to walk back out of his presence into their cars. Do not chase the lingering as a program; it cannot be scheduled. But notice it when it comes, and know it for what it is.