[tor-bugs] #19544 [Metrics/Metrics website]: Add graph on bridge users by country and transport

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#19544: Add graph on bridge users by country and transport
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     Reporter:  karsten                  |      Owner:
         Type:  enhancement              |     Status:  new
     Priority:  Medium                   |  Milestone:
    Component:  Metrics/Metrics website  |    Version:
     Severity:  Normal                   |   Keywords:
Actual Points:                           |  Parent ID:
       Points:                           |   Reviewer:
      Sponsor:                           |
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 The following idea came up in the
 [https://trac.torproject.org/projects/tor/ticket/10218#comment:20
 discussion to provide "users-per-transport-per-country" statistics for
 obfsbridges].  This ticket is about graphing existing data, whereas the
 discussion of reporting new data will continue on #10218.  Quoting a bit
 from that ticket to have enough context here:

 > It turns out that most large bridges (4 out of 5 on February 1, 2016)
 only see noteworthy usage via a single transport or have requests via one
 transport dominating the others in numbers (74% on the 5th large bridge on
 February 1, 2016).
 >
 > We could assume that the distribution by country is the same for all
 transports, that is, if `CC` (in `[0..1]`) requests came from a given
 country and `PT` (also in `[0..1]`) requests came in via a given
 transport, `x * y` requests can be attributed to that country and
 transport.  But that assumption may be wrong.
 >
 > What we could also do as first approximation is find a lower and upper
 bound of users by country and transport.  The lower bound would probably
 be defined as something like `max(0, PT + CC - 1)` (not just `0` to
 account for cases where `CC > 1 - PT`) and the upper bound as `min(PT,
 CC)`, even though I could be convinced that other formulas are even more
 correct.

 dcf kindly graphed responses by country and transport on #10218
 [https://trac.torproject.org/projects/tor/ticket/10218#comment:22 here]
 and [https://trac.torproject.org/projects/tor/ticket/10218#comment:24
 here], indicating that this approach may produce actually useful results.

 The next step was to perform these calculations in the database and
 transform number of responses to estimated user numbers.  I finally found
 time to work on that step.  Here's a graph on Tor Metrics which is yet
 "hidden" under "Advanced" until I'm more confident that it's doing the
 right thing.

 https://metrics.torproject.org/userstats-bridge-combined.html

 Example (image link to that graph, may look different over time):

 [[Image(https://metrics.torproject.org/userstats-bridge-combined.png)]]

 Next steps:

  - Become more confident in the particular math and code behind this
 graph.  Once that's done, move the graph to "Basic" so that people will
 find it.  I'm attaching a branch in a minute.

  - Make the user interface better.  For example, we could also graph top
 countries by transport, not just top transports by all countries or top
 transports in a given country.  Maybe we can graph other things using this
 data as well.

  - Make the raw data available.  There's a .csv file behind this graph,
 but I didn't put that on Tor Metrics yet, because we might have to change
 the data format and lack a versioning system to do that.  I'm putting up a
 [https://people.torproject.org/~karsten/volatile/userstats-
 combined-2016-07-01.csv snapshot of that file] (36.4M) for review.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/19544>
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