We've been asked (as we figured we would be), why we have two counts in our church visit reviews. We have "Our Rough Count" and "Probable Ushers' Count." The reason we say our count is rough is because in some churches it's hard to take an exact count. In a large congregation (hundreds or thousands) with people moving in and out, it is not going to be an exact count. But even in a small church, we might not get it right.
So we have the "Probable Ushers' Count" to cover people we might miss. There might be people up in the sound booth that we don't see; or in the church nursery or Sunday School classes, etc. On occasion, we'll see church bulletins with the count of people from the week before that seem rather incredible. We'll attend a church that seems to have 100 people but according to the bulletin there were 150 people the week before which is certainly possible, but it seems that whoever was counting not only included babies in the nursery and ushers counting money but also stray dogs crossing the property.
In our experience, inflation often is a part of church attendance counts.
But ushers' counts can go the other way. A pastor who asked us about our church counts said that their problem was ushers who counted too promptly. When a service started at 9:30 AM, the ushers would take their count at that time. But, shocking though this may be, there are people who are tardy to church. In fact, many people enjoy their breakfast or sleeping in or trying to get kids out the door, miss the announcements and sometimes more than a song or two (during her childhood, Mindy doesn't remember ever getting to church before the middle of the first hymn. And she lived next door). So the time of the count is certainly a factor as well.
And, of course, ours is always just one visit, a snapshot of a church. But we hope these numbers give you some idea of how God is working in various congregations and communities.