This discussion was held on the underlying Planet Money article [1] [2]<p>The problem then, and the problem now, is that this is arbitrarily defining middle class. Can't we just call this a boxplot[3] of income in major cities, and not make this into a discussion of what "middle class means"?<p>[1] <a href="https://news.ycombinator.com/item?id=9237345" rel="nofollow">https://news.ycombinator.com/item?id=9237345</a>
[2] <a href="http://www.npr.org/blogs/money/2015/03/19/394057221/how-much-or-little-the-middle-class-makes-in-30-u-s-cities" rel="nofollow">http://www.npr.org/blogs/money/2015/03/19/394057221/how-much...</a>
[3] <a href="https://en.wikipedia.org/wiki/Box_plot" rel="nofollow">https://en.wikipedia.org/wiki/Box_plot</a>