tracking downloads that come via Google

I noticed in Google WMT that Google sends most of my visitors to some of my download pages. (ending on .pdf). But somehow these do not show up in my download tab in clicky.

Somehow clicky does seem to be tracking people who are already on the site when clicking to the download page.

Does anyone have a clue as to why this difference occurs and what I can do to chance this?

Clicky cannot track from Google to a PDF as the tracking script does not execute and cannot execute on Google's pages nor a PDF.

As the tracking script is Javascript based, it does not execute on non-page based files (i.e. files that end in: .html, .php, .asp, .aspx, .jsp, etc...) that you do not have it on. Clicky is not some all knowing being, neither are other analytics tools, it only tracks the pages you have the script on and are capable of tracking.

At a high-level, the reason why a download is trackable via the path from your site to the PDF is that the tracking code executes on your page, see's you have a ".pdf" link on it and "tracks" it as a download when clicked. Going from Google straight to the PDF, you bypass the tracking code thus Clicky doesn't know about that action.

Just re-read my statement, correction:

* it does not execute on non-page based files (i.e. it only executes on files that JS can run on usually: .html, .php, .asp, .aspx, .jsp, etc...)

Thank you for your clear and concise answer. I guess I'll just have to live with it, but at least I know the reason now, and as usual the logical explanation is comforting.
Have a good weekend!