1. Is the NBA more “top-heavy” now than it has been throughout its history?
  2. Are the conferences more “imalanced” than they have been throughout history?

Requires an answer to each of these questions first:

  1. What does it mean for the NBA to be “top-heavy”?
  2. What does it mean for the NBA to have “competitive balance” between and within the conferences?

We’ll look at the last 30 years of NBA seasons, including only the top 50% of teams in each conference (what the bottom is like doesn’t seem relevant to the question of “top-heaviness”). We’ll use scaled ranks for the teams within a conference, to facilitate comparison across years (since the NBA has added teams several times in recent decades).

measuring ‘top-heaviness’ across NBA seasons

linear models for wins ~ rank across NBA seasons (top 50% of teams)