

Uberdata: Rain's Effect on Uber Ridership - MikeF
http://blog.uber.com/2011/03/12/uberdata-uber-for-style-and-comfort/

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FiReaNG3L
Talk about a misleading chart, cumulative rides on the axis. Looking at the
slope since last November, it's pretty linear, which would imply no growth at
all.

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voytek
Man you folks are more harsh than peer-reviewers! :)

And here I was thinking to myself when I wrote the post, "people don't want to
be drowning in data; they want something interesting based on the data". Dang.
I was wrong!

On its own, that chart would be shady, you're right. For the purposes of the
data I was trying to show (that weekend and weekday rides are quite similar),
that was the best way to plot the data.

Of _course_ if I take a linear function, and plot its integral, it will be
exponential. By definition. I recognize that.

But that's why I also plotted the weekly averages farther down. You can see
the non-linear growth very clearly in that chart. In fact, if I log-transform
the average rides per week, the plot is quite linear (as would be expected for
exponential growth). r(ln(rides)) = 0.83

Your comment about the slope since last November being "pretty linear" is
misleading, too, though!

If you take an exponential function, and arbitrarily select _any sub-segment
of it_ , that sub-segment will _always_ have a better linear fit than the
linear fit for the whole function.

So by definition, mathematically, you're right. Our growth since November has
been more linear than the overall history of our growth. Just as the first
three months were also more linear. Or during any other arbitrary time period.

So I happily submit my revised manuscript for your reconsideration. I hope I
have adequately and thoroughly addressed all of the reviewers concerns. Thank
you.

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gojomo
_...black swan events such as holidays..._

The 'black swan' has definitely jumped the shark if it's now being used to
describe events that arrive so reliably they can be printed on calendars,
years in advance.

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voytek
Touché. I was definitely being technically unclear. My usage there was meant
to indicate that the _effect_ of the holidays on ridership was wildly higher
than we had expected. Now that we've had a few holidays, we can begin to build
that crazy surge into our models.

So yes, certainly the holidays _themselves_ are predictable, but their
_effect_ on rides was not.

But now is. :)

~~~
SkyMarshal
On another note, glad you guys have expanded to Palo Alto. I'm moving up there
end of the month, and will be relying on you and a bike for transport.

Was not impressed with public transportation in SF either. Got off the
Caltrain on my first visit to the city a few weeks ago, and was expecting a
line of cabs waiting outside with train arrival schedules glued to their
steering wheels, but not a single one. WTF. Wished I'd known about Uber that
night, would have saved me a hike to Market St.

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joshu
I guess someone is trying to emulate the okcupid folks, albeit with less
interesting data.

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dweekly
Hilarious. :)

