This number is significant in ministry to the number of persons a pastor can effectively pastor at any given time. So, if you church has more than 150 members, one might say you need another pastor. I heard this told in seminary as an offhand figure for when it was time to hire another pastor, without corroboration, but seemed quite reasonable. Now, I know better.
The problem is not Dunbar's Number
. That seems to be a pretty good fixed constant. The problem lies in how much it costs to maintain a full-time pastor.
Lyle Schaller wrote in 2003 that it takes a weekly attendance of about 125 people to maintain a full-time pastor and pay for the other upkeep of a church. That number has only gone up since 2003.
Life is getting harder for the local church to support a local full-time pastor. To that end, the local church, and the local pastor (full-time of any denomination/title) will need to learn to live in a different economic and social climate.
I am not sure of all the changes. But, I can tell you this: if the 125 people that it takes to support a full-time pastor each takes the responsibility of Dunbar's Number for themselves, and begins to fill in the remainder of 150 people, then the circle draws even wider, and more ministry can be done. To that end, I promise to be training leaders to grow and live into their role as Discipling Mentors.
BTW-for a quick read of a sermon by Mark D. Ridley in Vestal New York, where I found Schaller's information, and his sense of Dunbar's Number, even without naming it, CLICK HERE