From CFO Maestri on the Q&A call with analysts: "2:15 pm: We had the benefit of a 14th week, but this was offset by several factors including less channel fill than last year and a one-time $548 million patent judgment receipt last year."

http://www.macrumors.com/2017/01/31/q1-2017-results/

Channel fill is fairly irrelevant (whose fault is it that your distributors don't want more of your stuff "just in case"?) and the cash is also fairly irrelevant - what matters for momentum is the number of units shifted and that's lagging everywhere except iPhones (and, if you trust them, the Watch).

Except you're adding a weak week, not a week that's expected to compete on an even basis with a typical holiday-quarter week, so that math isn't exactly telling/accurate either.

Interesting. Thanks for pointing that out.

> For accounting purposes, a firm is allowed to define a "quarter" as either a span of 3 months or else a span of 13 weeks. A "year" is then four quarters. ... Consequently, a firm that defines its quarters in terms of weeks needs to hold a 14-week quarter every four or five years. [1]

[1] http://www.slate.com/blogs/moneybox/2014/02/06/_14_week_quar...