[oncallthrow]

But that isn’t how you calculate market share, so what you’re saying is nonsense.

[msgilligan]

There are multiple ways of calculating market share (e.g. units vs dollars or for different time periods) but assuming it is measured in dollars for a quarterly time period, how would you calculate the market share based upon my sample data above?

[oncallthrow]

(company sales in period - company returns for sales made in said period) / (industry sales in period)

[matt_kantor]

With this formula market share for past periods can keep changing arbitrarily far into the future (depending on the companies' return policies).

[oncallthrow]

Yes.

[msgilligan]

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.

[oncallthrow]

Presumably by a journalist who doesn’t understand what market share is

[estimator7292]

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