Elo as a Skill-O-Meter

Whether a game counts as &ldquo;skill&rdquo; or &ldquo;chance&rdquo; isn&rsquo;t just a pub argument — in many countries it&rsquo;s a legal distinction. Roulette and blackjack live on the &ldquo;chance&rdquo; side; tennis and chess are filed under &ldquo;skill&rdquo;. Different rules, different taxes, different ways for people to lose money. The trouble is that this line is usually drawn by…