Loved this post from Dr. Drang, on how to accurately visualize the declining trend in iPad sales:
There are myriad other ways to smooth a graph without switching to
cumulative figures. One of the simplest is the moving
average. In this
technique, instead of plotting the raw data, you plot the average
of a few data points in the neighborhood of each time value.
For many data sets, the best size of this neighborhood is not
obvious. With Apple’s sales figures, though, I think it’s clear
that the best choice is to average over four quarters: the quarter
that you’re plotting and the three previous. This smooths over the
seasonal jumpiness while not including so much past data as to
ignore real trends.
As for why iPad sales have hit this slump, I really liked this explanation from one of Drang’s readers:
Ben Packard, in an email, suggests my reason for dismissing the
durability explanation for the iPad sales decline is weak. The
Mac, he says, has been around long enough for there to be
substantial numbers of owners at every stage of ownership, but far
more iPad users are still on their first iPad. Whatever the long
term replacement cycle of iPads turns out to be, we’re still in
the first one, too early for variations in when people bought
their most recent iPad to have evened out.
★ Thursday, 30 April 2015