[tor-bugs] #5807 [Analysis]: Propose better bridge usage statistics

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#5807: Propose better bridge usage statistics
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 Reporter:  karsten                      |          Owner:  karsten 
     Type:  enhancement                  |         Status:  accepted
 Priority:  normal                       |      Milestone:          
Component:  Analysis                     |        Version:          
 Keywords:  SponsorF20120701 tor-bridge  |         Parent:  #3261   
   Points:  14                           |   Actualpoints:          
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Changes (by karsten):

 * cc: nickm (removed)
 * cc: arma (added)
  * component:  Tor => Analysis
  * milestone:  Tor: unspecified =>


Comment:

 Here are the results from a more detailed analysis.  This analysis covers
 all data we have, which means September 2011 until now.  Bridges did not
 report directory requests to the bridge authority before that.

 [[Image(ticket:5807:bridge-dirreq-stats-2012-10-02.png)]]

 See the comment above for explanations of lines 1 to 5.  The new line 2a
 shows the number of consensuses published on a given day.  I discovered
 that the spikes in directory requests (line 1) coincide with missing
 consensuses on the same day.  This makes sense, because clients would
 request consensuses more often if they canot get a recent enough
 consensus.  We'll have to discard those days from the estimated bridge
 user numbers.  This also applies to direct user estimates, by the way.

 So, line 4 is the new estimate for daily bridge users from all countries
 and line 5 is the estimate for a single country, here Syria.  As I said,
 the new numbers are much smaller than the old numbers, but I have much
 more confidence in this estimation method.  The old approach is wrong with
 respect to absolute numbers and was only deployed back in 2009 to observe
 relative changes over time.

 The next step will be to a) write down the new algorithm in a tech report
 and b) implement it on the metrics website (probably along with the old
 graphs for the moment, not replacing them yet).

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/5807#comment:10>
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