Engagement
Download tracking
Also called file download event.
Download tracking is recording clicks on file URLs such as PDF or ZIP as events. It shows which documents people take away, which pageviews cannot.
How it is measured
Match links whose path ends in a known extension and send an event with the file name. A direct link to a file does not load a page, so without this nothing is recorded at all. Server logs are the cross-check.
Tarsier has no automatic download event. Attach its event call to the file links you care about, and use the name of the file as the label.
Worked example
A city council posts minutes as PDFs. The minutes page gets 900 pageviews a month, but the file events show 1,350 PDF opens, of which 610 are one file: the budget summary.
The council turns the summary into a web page. Reading rises, and the PDF count drops to 140.
How it differs
Download tracking records file clicks. Click tracking records any chosen click. An automated event is one the script detects without per-link setup. A download counted is not a file read.
Common errors
Tracking the link and missing direct links shared by email. Counting a prefetch as a download. Comparing counts to server logs without allowing for bots. Forgetting extensions like docx and xlsx. Treating a download as a lead.
In practice
Start with the three file types you offer most. Review the top downloads each month and ask whether any of them should be a page instead.