All about PDFs in search

[RyanD.]

I'm trying to track down some information on how PDFs work in Google Analytics, GWT, and Google SERPs. We don't have very many PDFs on our website but suddenly, in the past 4 or 5 months, one of our hidden-in-the-corner-of-the-server PDFs is outranking our homepage for a specific search term. That's led me to some investigating in Google Analytics and GWT, which has led to more questions.

To be specific:

1. Has Google changed how they index/crawl PDFs and how likely they are to show up in SERPs?

2. Some of my PDF URLs show up as "Pages" in Google Analytics, but not all of them. How does Google know Pageviews, time on page, etc. for these PDFs since there's no tracking code on them?

3. The PDF URLs show up more reliably in Google Webmaster Tools > Search Traffic > Search Analytics. The "# clicks" in GWT is way different than the Pageviews in GA, though, like 500:1 different. One reason I'm suspecting is that Google Analytics is only showing how many times the PDF link was clicked on from a webpage, whereas GWT is showing all of the clicks when the PDF showed up in SERPs. Does that make sense?

Any insight would be appreciated! Thanks!

-Ryan

[GlobeRunner]

Ryan, the Google Analytics tracking code is not implemented in a PDF, it's only actually implemented (the JavaScript code) by the user's browser. So, you're exactly correct:

Google Analytics is only showing how many times the PDF link was clicked on from a webpage, whereas GWT is showing all of the clicks when the PDF showed up in SERPs.