Thursday, October 1, 2015

STATS – Mormons October 2015 – Actuarial Evaluation of President of the Church

UPDATEDElder Rasband, Elder Stevenson, and Elder Renlund

This post assumes you have some knowledge about The Church of Jesus Christ of Latter-day Saints (a.k.a. LDS or Mormons). If not, the short story is here.

I built this model for fun. Expected future lifetimes are volatile. It may be interesting to observe general trends, but don't bet your money on this.

The idea of the table above is to use actuarial methods to calculate the probability of an apostle becoming president of the Church. Note that colloquially among Mormons is that this person is referred to as "The Prophet". The model I wrote simulates the future of each apostles' mortality and subsequent seniority rank. Seniority among the apostles is based on how long they have held the title of Apostle and not by age. If you have held the title the longest out of all the apostles then you because president of the Church (because you're rank 1). Succession of the prophet is based on that same ranking system. For example, if the Prophet dies all apostles moves up in rank and rank 2 becomes rank 1 and also the new president. 

Similar to the 2014 simulation, the methods for this simulation have not changed much. I have adjusted the mortality tables some more. Note, that the simulation calculates in year-long steps. Let's say a prophet dies in February of 20xx. In this simulation the prophet would be given credit for the whole year of 20xx and the new prophet would not be counted until year 20xx+1. This also means that you can not have multiple successions in the same one year period. Maybe next year (like I said last year...) I'll update the code to do monthly iterations and we can examine partial year data.

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  1. This is very interesting. Thank you for your research.

  2. Thanks, DQ! Excited to see what this looks like with the new apostles added in.

  3. Very interesting. KNOW WHAT I WOULD LOVE? I would love to see old actuary charts and see how often people became prophet when it was statistically not likely and vice versa. But like you said, God's hand is in every prophet being called. Thanks again.

  4. How are you determining 'Expected Age at Death'?

  5. Very interesting! Any chance you could add a "t" to the name of Christ in the table's title?

  6. (1) The spelling should be fixed.

    (2) "Expected Age at Death" is their mean age in the simulation when the uniform random variable surpasses the threshold of the mortality probability. For example, the internal steps in the simulation might look like this.

    Simulation cycle 1: President Monson is age 88
    Simulation cycle 1: Probability of one year survival mortality on a life age 88 = 0.848377
    Simulation cycle 1: Random uniform variable = 0.514577
    Simulation cycle 1: Random variable < survival mortality, President Monson survives one year
    Simulation cycle 2: President Monson is age 89
    Simulation cycle 2: Probability of one year survival mortality on a life age 89 = 0.835047
    Simulation cycle 2: Random uniform variable = 0.991944
    Simulation cycle 2: Random variable > survival mortality, President Monson dies at age 89
    You do 50,000 simulations, each with about 75 cycles, and then you take the arithmetic mean of the death ages across all 50,000 simulations for that person to arrive at “Expected Age at Death”.

  7. This is so freakin sweet. It's actually gold!

  8. This is fascinating. I'll second John Bushman's request, it'd be interesting to use this same process with the apostles in 1965, 1975, and 1985, and then overlay the actual presidential succession to see how good a predictor this approach might be.

  9. Cool chart DQ. Do you plan to update this with the recent (2018) changes? Perhaps waiting until the new apostles are called at the Spring conference?