Tithing is the main source of income for the Mormon church (Ostling & Ostling 2007, p. 404) but the amount received is unknown because the church does not provide financial transparency or accountability – not even to its members. Estimates from researchers and journalists range from $ 5 to 8 billion per year. Using a Monte Carlo simulation, Mormonism101.com arrives at a much lower estimate of about $ 3.5 billion.
On the Mormon church’s news website, membership numbers are listed by country and by continent. However, these numbers do not reflect Sunday attendance, let alone tithe paying members. Since the Mormon church doesn’t publish actual attendance records, these activity rates from Mormon researcher Matthew Martinich were applied. This yields a total active membership of about 4.5 million (data accessed on January 13, 2015).
For each country, average income was determined using the IMF World Economic Outlook database (GDP per capita, current prices). In a few cases where this data was not available (mostly small, exotic oversees territories like Saint Kitts and Nevis or Saint Vincent and the Grenadines), Wikipedia and the CIA World Factbook were used to complete the data (data accessed on January 13-14, 2015).
In theory, tithing revenue is 10% of the number of active members, times their average income. This would yield an impressive $ 16 billion per year. In practice, however, not every active member pays tithing, and not every tithe paying member pays the full 10% over the average national income. To accommodate these uncertainties, the model uses a range of tithe payers of 5-35% of the active members.
The activity rates, however expertly put together, are also uncertain. Each activity rate is, therefore, placed in a 10% bracket (e.g. an activity rate of 14% is classified in the 10-19% bracket) and the model uses this range to simulate different activity rates.
A Monte Carlo simulation is a method to combine multiple uncertainties and calculate a statistically reliable outcome. With each simulation run, the two uncertainties in the model – activity rate and number of tithe payers – are chosen at random within the given range.
In the table above, for instance, the first colum contains random percentages of tithe payers in the 5-35% range. In the next columns, a random activity rate is generated per activity bracket, e.g. 10-19% in the second column.
Activity and tithe paying rates are then multiplied into an uncertainty factor, for example 5.94 x 10.54. This is repeated 100,000 times to ensure that, although the values on each line vary wildly (though within the set bounds), together they yield a statistically reliable average result.
The result of $ 3.5 billion is as reliable as the estimate of the activity rates and the percentage of members paying tithing. Unfortunately, the Mormon church does not disclose this information either. What, then, is the value of this model?
- For one thing, it explains why Mormon church leaders preach about tithing so often. An increase of only 1% in the number of tithe payers worldwide yields an extra $ 175 million in tithing revenue - a leveraged 5% revenue increase.
- Earlier versions of the model, run with data from 1998 and 2006 also accurately predicted where new temples would be built. Regression analysis showed that a high value for [number of active members] x [GDP] was a reliable predictor temple building activity.
- Also, the model indicates that a whopping 85% of all tithing revenue comes from the United States, with Utah alone bringing in some 60%. Despite the Mormon church’s aspirations to be a global church, Mormonism still is a primarily American business.
- Finally, the model can be used to validate other tithing revenue estimates. For example, to yield $ 8 billion in tithing, the model shows that 45% of all active members must pay a full 10% of their country’s average income. Whether such assessments and inferences are accurate remains open to interpretation until the Mormon church embraces financial transparency.