Updated 1/4/2019

The rate of growth in the Mormon Church is on a sharp decline (from 6.2% in 1990 to 1.2% in 2018) .

What’s Happening?

The rate of membership growth can be represented by this equation: R g = R b + R c - R d - R r . Where:

R g is the rate of growth (about 1.2% in 2018),

R b is the birth rate (about 3.4% for American Mormons ),

R c is the growth rate attributed to new converts (about 1.4% ),

R d is the death rate (about 0.7% for Utahns ), and

R r is the rate at which members leave .

If we assume that the respective rates for the entire Mormon Church are similar, then the rate at which people are currently being removed is about 2.9%.

I’m sure that it’s troubling to Mormon leaders that people are leaving Mormonism at double the rate that people are converting to Mormonism.

My Assumptions

A few people have questioned my assumptions in extrapolating R b and R d to the general Mormon population. In response, I did a sensitivity analysis on these two #s to see how reasonable variations in those #s affect the final result. This is what I got: varying R b from 4% to 3% changes R r from 3.4% to 2.4%. Varying R d from 1% to 0.5% changes R r from 2.5% to 3%. These are very conservative variations IMO. In extreme scenarios (which are not reasonable IMO) R r could actually be as high as 3.6% and as low as 2.1%.