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Are we decentralized yet?

(arewedecentralizedyet.online)
487 points Bogdanp | 6 comments | 30 Aug 25 19:26 UTC | HN request time: 0s | source | bottom
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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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oncallthrow[dead post] ◴[30 Aug 25 21:15 UTC] No.45078073[source]▶
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msgilligan ◴[30 Aug 25 21:26 UTC] No.45078146[source]▶
> The only way that makes any sense is if you subtract returns for sales made in a different period to the sales period you are considering

Exactly. That's the way accounting works. They did not know in the previous quarter that the product would be returned in the following quarter, so they end up having negative sales in the current quarter.

Yes it produces "garbage output", which I find amusing.

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oncallthrow ◴[30 Aug 25 21:27 UTC] No.45078152[source]▶
But that isn’t how you calculate market share, so what you’re saying is nonsense.
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1. msgilligan ◴[30 Aug 25 21:41 UTC] No.45078229[source]▶
That is how it was calculated in a published trade magazine (either Infoworld or MacWeek, I think) I'm not sure if the the analysis was done by a market research firm or the magazine.
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2. oncallthrow ◴[30 Aug 25 21:44 UTC] No.45078251[source]▶
Presumably by a journalist who doesn’t understand what market share is
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3. estimator7292 ◴[30 Aug 25 23:14 UTC] No.45078844[source]▶
Everybody else is telling you you're wrong and you're doubling down and insisting that respectable journals are morons who don't understand anything.

You should stop, reflect on this fact for a moment, then go pick up a goddamn book

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4. ◴[31 Aug 25 00:20 UTC] No.45079210{3}[source]▶
5. ◴[31 Aug 25 00:24 UTC] No.45079224{3}[source]▶
6. ◴[31 Aug 25 00:44 UTC] No.45079334{3}[source]▶