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Are we decentralized yet?

(arewedecentralizedyet.online)
487 points Bogdanp | 4 comments | 30 Aug 25 19:26 UTC | HN request time: 0s | source
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msgilligan ◴[30 Aug 25 20:45 UTC] No.45077856[source]▶
TIL about the Herfindahl–Hirschman Index and I wanted to test it with a weird corner-case that I remember.

At one point in the late 1980's Microsoft had a GREATER than 100% market share of the Macintosh spreadsheet market.

How is this possible?

Market share (for a given period) is the participant's sales in the market divided by total sales. It just so happened that Lotus had more returns than sales of their failed spreadsheet, Lotus Jazz. So Lotus, had a negative market share and Microsoft had more sales of Excel than total sales in the market, resulting in a greater than 100% market share.

I don't remember the exact numbers and I believe there was at least one other competitor in the study. But let's just say the numbers were:

Microsoft: 102% Lotus: -2%

In that case the Herfindahl–Hirschman Index would be 102^2 + (-2)^2 = 10404 + 4 = 10408.

So, in this pathological case it is possible for the HHI to exceed 10,000.

Edited: Added (for a given period) above, for clarity.

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tomrod ◴[30 Aug 25 22:07 UTC] No.45078403[source]▶
HHI is a super useful metric -- glad you like it!

The squared sum of normalized shares proves to be very useful in a lot of contexts -- not just market share. Voting is one great example.

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msgilligan ◴[30 Aug 25 22:17 UTC] No.45078481[source]▶
Sounds depressing (i.e. ~5000 in a typical US election)
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tomrod ◴[30 Aug 25 23:22 UTC] No.45078890{3}[source]▶
It gets really interesting when you look at the precinct and county level in the US, and similar types of views in European countries where they do real representative government.
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1. fakedang ◴[31 Aug 25 02:04 UTC] No.45079681{4}[source]▶
It's ironic that national level politics mirrors the kind that the founding fathers did not ever want happening, while local politics has the kind of representation that they actually had in mind (in most places).
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2. naniwaduni ◴[31 Aug 25 02:44 UTC] No.45079894[source]▶
I'm not sure that is ironic.
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3. asdfasvea ◴[31 Aug 25 13:47 UTC] No.45083126[source]▶
No it's definitely ironic, in the rain on your wedding day kind of way.
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4. tomrod ◴[31 Aug 25 18:45 UTC] No.45085815{3}[source]▶
Which is to say, the ultimate irony of Ms. Morisette's song is that there is no irony named.