Vanity metrics

Our church has 1,000 members!
Measuring numbers of the current moment alone (a snapshot) is a vanity metric: any number looks good, but the number alone tells you little. Often, the number is just used to make you feel or look good.
Two numbers over time can give you growth rates, which show the reality of the situation.
Our church had 500 members in 2005, and 1,000 in 2015–we doubled in a decade.
To calculate the exponential growth rate, the formula is ((Present/Past)^(1/(years))-1.
Or, in the above example, ((1000/500)^(1/10))-1, or 0.071, or 7.1%.
The rule of 72 (72/AGR, or 72/7.1, or 10.1, tells you how long it will take to double again at the present growth rate.
Numbers without growth rates can hide the reality of stagnation.
Growth rates without numbers can hide the reality of small numbers.
We grew by 100% per year! (We went from 2 members to 4.)
Measuring numbers against a goal gives you scope of task remaining.
Our church has 1,000 members, and there are 100,000 people in our city. 99% of the task remains. It took us 20 years to get to 1,000 members. At that rate, it would take 20 * 99 or ~1,980 years to get to the whole.
Measuring current position against position last year and against goal in the future gives you strategic critique:
Do we want to take two millennia to see our city largely Christianized?
Anything that isn’t (and, most likely, can’t be) measured against a goal: I suspect it’s a “vanity” metric meant to look good on a report.

Monetizing Halloween

Costumes, candy, decoration sales: $7.4 billion
Pet costumes: $350 million (fastest growing category, up 59% since 2010)
Candy: $2.2 billion
Average alcohol consumption rises 30% when it falls on Friday or Saturday
Adult costumes: $1.3 billion
Kid costumes: $1.06 billion
Popup haunted houses, mazes, amusements: $300 million
Voigt, Kevin. “Halloween, once for kids, has become an adult holiday.” Christian Science Monitor.

How long it takes

Perhaps the question is not how long it takes to disciple someone to maturity, but rather how long it takes to get someone on the path to following Jesus. Only Jesus can fully disciple someone. Are we ever fully mature?

Children who become Christian

For an article, I’m working on tracking down this “71% Christians got saved young” figure to understand it better. Looking for the original source.
Wikipedia post on Child evangelism movement pointed me to:
The Great Commission to reach a new generation,” Thom Rainer, 1997, SBTS
Evangelism is most effective among kids,” Barna, 2004
The Bridger Generation,” Thom S. Rainer, 2006
Also been referred to research by OneHope. An initial review shows this to be interesting.
My own speculation is that most Christians got saved young because they grew up in Christian households. I’m looking to see if the original research cited here distinguishes between converts who were in Christian homes vs converts who were in non-Christian homes. (45 million babies born to Christian homes vs 15 million converts in from non-Christian homes, globally, per year, according to Global Religious Dynamics.)