## Tuesday, May 11, 2010

### Special Guest Question from Desiree Schell

Today’s question comes from Desiree Schell, the host of the very entertaining and thought-provoking Skeptically Speaking.  Desiree wants to know,  “How many dice rolls in all the role-playing games in an average year?”

Judging from my fairly eclectic group of friends, I would estimate that about 1% of people play role-playing games fairly consistently1.  By “consistently”, I mean they play about once a week or about 50 times per year.  I’m assuming the majority of players play consistently.  Games will differ in how often a player rolls, but it’s not uncommon for a player to roll about 1000 times2.  From this, we can easily compute the number of rolls in an average year:

# of rolls = (fraction of players) · (# of people) · (rolls per player per game) · (# of games)
= (0.01 players/person) · (6.7×109 people) · (1000 rolls/player/games) · (50 games)
= 3.4×1012 rolls

That’s 3.4 trillion rolls.  If you add up the gravitational potential energy from all these rolls, it’s about a third of the energy released by a nuclear bomb.  Thanks for the question, Desiree!

You can hear Desiree on Skeptically Speaking Fridays at 6pm MST, or you can follow her and the show on Twitter at @teh_skeptic and @SkepticalRadio, respectively.

[1] Some might quibble with my 1% assumption.  I would argue it’s a good order of magnitude estimate.  If I chose 10 people at random, there’s a good chance none of them are into role-playing, so the actual number is almost certainly less than 10%.  However, if I go through 1000 people at random, there’s almost certainly going to be one person into role-playing, so it’s probably greater than 0.1%.
[2] I cheated a little here.  This number seemed much too large, but I consulted my friend Josh who is more into gaming than I am, and he assured me that it’s a good estimate.  Thinking back to my days playing Risk (where you roll multiple dice for hours), I figured it’s good to within an order of magnitude.