Thanks for the detailed analysis Oliver.

I think the page view definition is always going to be somewhat fungible. I suspect that when people start watching the impact of new features on the numbers, we'll get more attention.

-Toby

On Fri, Feb 6, 2015 at 3:05 PM, Nuria <nuria@wikimedia.org> wrote:
I think an important thing for the new definition is that is easy to update, as any definition we come up with will need updating and maintenance.



> On Feb 6, 2015, at 2:56 PM, Oliver Keyes <okeyes@wikimedia.org> wrote:
>
> *nods glumly*. Every day we turn over a rock and find a new ants nest.
> I'm waiting for the day, probably about 30 seconds after we declare it
> The Definitive Pageviews Definition, when we start finding flaws in
> the new one ;p.
>
> I feel like we should append to the end of the current Rules of
> Analytics something like "Nothing will make you more cynical about a
> class of metrics than trying to implement them"
>
>> On 6 February 2015 at 17:22, Erik Zachte <ezachte@wikimedia.org> wrote:
>> Yes, this has been an issue before. Squid log based reports filter these banners for years, but only after a similar distortion became very apparent, and a lot of data needed to be repaired.
>>
>> -----Original Message-----
>> From: analytics-bounces@lists.wikimedia.org [mailto:analytics-bounces@lists.wikimedia.org] On Behalf Of Oliver Keyes
>> Sent: Friday, February 06, 2015 22:04
>> To: A mailing list for the Analytics Team at WMF and everybody who has an interest in Wikipedia and analytics.
>> Subject: [Analytics] Drop in Commons mobile traffic - a diagnosis
>>
>> Hey all,
>>
>> The pageviews stored at stats.wikimedia.org and the Vital Signs dashboards showed a substantial drop in pageviews to Wikimedia Commons, primarily from mobile, beginning on 1 January 2015. I was tasked with investigating and I'm reporting what I found so that we have a note of the problems this brings up.
>>
>> From an investigation of requests to that site at that time, it appears that this is a perfect storm of known deficiencies in the legacy pageviews definition, fundraising changes, and mobile changes.
>> To summarise:
>>
>> 1. The legacy Pageviews definition contains Special pages, including Special:BannerRandom and Special:HideBanner; 2. The mobile website was historically loading things from Commons in such a way as to trigger calls to Special:HideBanner, which were picked up by the legacy definition as "pageviews to commons"; 3. The Mobile team deployed changes to their image loading setup at the end of December that stopped this from happening, and that coincided with the disabling of the Fundraising primary campaign.
>> 4. The result of this was an apparent massive drop in traffic to Commons from the mobile site - when the actual inaccuracy was the inclusion of that traffic in the first place.
>>
>> There are several lessons to be learned from this. First, it is worth reiterating the deficiencies and inaccuracies inherent in the legacy pageview definition, many (but certainly not all) of which centre on how it treats the fundraising banners. We are working as rapidly as we can to completely deprecate this definition, replacing it with a new one which is not subject to this kind of variation. We are currently in the middle of performing final QA testing on the new definition:
>> once it is satisfactory, we will deploy it as soon as humanly possible and deprecate the legacy definition.
>>
>> Second, let me emphasise how critical it is that the teams building MediaWiki and our instances of it - Platform, Operations, Mobile, you name it - keep us in the loop about changes that they make. This was a very dramatic shift in client logic around requests: it flew under our radar. We should have a process in place for letting Analytics know about these changes before they happen so that we do not end up with inaccurate data and a constant game of catchup.
>>
>> Thanks,
>>
>> --
>> Oliver Keyes
>> Research Analyst
>> Wikimedia Foundation
>>
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>
>
>
> --
> Oliver Keyes
> Research Analyst
> Wikimedia Foundation
>
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