Membership Flow Model

Central estimate

central[t] = central[t-1] + converts[t] + child_of_record_baptisms[t] - deaths_of_active_members[t] - inactive_members_reaching_age_110[t] - names_removed[t]

High-retention scenario

high[t] = high[t-1] + converts[t] + child_of_record_baptisms[t] - deaths_of_active_members[t] - inactive_members_reaching_age_110[t] - 0.75 * names_removed[t]

Low-retention scenario

low[t] = low[t-1] + converts[t] + child_of_record_baptisms[t] - deaths_of_active_members[t] - inactive_members_reaching_age_110[t] - 1.25 * names_removed[t]

Starting population

The model starts from the reported membership total in 1950.

Confidence: medium

Membership additions

Convert baptisms and children-of-record baptisms are treated as membership additions. New children of record are not treated as same-year member additions.

Confidence: high for recent official reports; lower for estimated historical cells

Children-of-record pipeline

New children of record are record-intake events for children who are not yet baptized. They become membership additions only if later baptized as children of record, usually around age 8. Those baptized at age 9 or older are counted in convert baptisms, so the pipeline can leak into the convert statistic.

Confidence: medium for the concept; low to medium for post-reporting-gap estimates

Losses

Deaths of active members, inactive members reaching age 110, and names removed are treated as record exits. These fields are model inputs, not official annual report categories.

Confidence: low to medium

Uncertainty band

The high- and low-retention scenarios vary the names-removed component by plus or minus 25%. The band is a sensitivity test, not a statistical confidence interval.

Confidence: medium as a sensitivity display; low as a probability statement

Activity excluded

No attendance, belief, or activity adjustment is applied. Activity proxies are useful comparison indicators but should not be subtracted directly from membership records.

Confidence: high