The Simpsons, actuarially

The animated series “The Simpsons” has been on television since 1990.  This remarkable run made me wonder, “What were the odds in 1990 that the main voice actors for the show would survive to 2017?” I did some actuarial analysis to find out.

tl;dl: 46%

This number is higher than I expected, mostly because most of the actors were very young in 1990. Here’s how I calculated it.

The Simpsons had six key voice actors from the beginning.

• Yeardley Smith (b. 1964, Lisa), 95.9% likely to survive
• Hank Azaria (b. 1964, Moe etc.), 93.2% likely to survive
• Nancy Cartwright (b. 1957, Bart), 92.9% likely to survive
• Julie Kavner (b. 1951, Marge), 89.0% likely to survive
• Dan Castellaneta (b. 1957, Homer), 88.7% likely to survive
• Harry Shearer (b. 1943, Burns etc.), 70.0% likely to survive

The cumulative likelihood of all surviving is the product of these probabilities, or 45.8%.

If you omit Shearer and Azaria and count only Simpsons family members (Marge, Homer, Lisa and Bart), you get 70.2% odds of surviving to 2017.

The caveats to this analysis are interesting.

This is a backward-looking probability analysis, which is always dangerous. I’m only prompted to do this analysis after realizing the the six key actors are all still alive.  like selecting a random number between 1 and 100 (64, for example) and saying, “Wow, there was only a 1% chance of getting 64 – how odd!” We have to frame the question carefully.  I can’t say “What are the odds that the six main voice actors from the Simpsons are alive?”  I have to say, “What were the odds in 1990 that the six main actors would survive to 2017?”

Voice actors can be replaced. The death of one of the six would not necessarily have collapsed the show.  Kermit the Frog has been voiced by several actors since Jim Henson’s death.  I do a pretty fair Groundskeeper Willie and I’m standing by if needed.   (But if we lose Hank Azaria let’s just let Apu go)

My selection of the six key voices is somewhat arbitrary.  The Simpsons cast has lost some great voices, most notably Marcia Wallace (d. 2013, Edna Krabappel) and Phil Hartman (Lionel Hutz/Troy McClure).    Probably the next two essential voices from the early days were Pamela Hayden (b.1953, Milhouse etc.) and Russi Taylor (b.1944, Martin Prince etc.)

This analysis uses U.S. Social Security actuarial tables from 2014.  Health care probably improved a bit between 1990 and 2014, but probably not by too much. Also, I ignored individual birthdays and rounded by year. The tables distinguish between men and women, which is why Nancy Cartwright had better odds of surviving than Dan Castellaneta, who was the same age.

This analysis assumes independence of outcomes – that one cast member’s survival didn’t meaningfully affect the other member’s chances.  It ignores both positive and negative correlations.  It could be true that working together on a creative endeavor collectively improves survival outcomes.

There’s a slight positive survival bias because all of the actors were not just alive in 1990, but also healthy enough to work.  Are healthy working actors more likely to survive than most people their age?  Probably.  Then again, all six are still healthy to keep working today, which is somewhat less likely than mere survival.