Tom,

I'm not sure what problem you have with Chris Smith's measure. It surely isn't enough to just write Chris Smith's adorable but unsupported belief that income disparity is a useful measure of anything.

In one respect, it measures precisely what he says is measures: standard deviation in incomes. Is it a commonly used measure? My brief websearch says "no;" instead, income is typically broken up into fifths and income disparity is measured by the gap between the top and bottom fifths (percentage of total income earned; average income in each fifth; rate of growth of income).

Now Chris further claims that this provides us information about a) the gap between rich and poor and b) the health of the middle class. I don't think it provides any information on (b) but it may help us understand (a), right?

So final question is do we care if we have high or low income disparities? I'm not sure how you feel about that, since you don't make your position clear, but another brief websearch finds that large income disparities are generally viewed as a bad thing.

And I agree with Chris on this one. I'd ask Cmmr. Sam to make sure that any measure of economic success comprehend the whole city of Portland, and not just the Pearl/Ladds/West Hills triangle that seems to drive so much of City policy and politics. Measuring income disparity is one way to get at this.