Session Duration
Average session duration doesn't measure how much people like your site. It measures how long it takes a visitor to find, or fail to find, the answer they were looking for.
“An eight-minute session can mean a visitor fascinated by your content, or a lost visitor who can't find the link they were looking for. The number alone doesn't distinguish the two cases.”
Otto GTM ObservatoryInterest and frustration produce the same number
Average session duration, taken in isolation, doesn't distinguish between a visitor carefully reading valuable content and one struggling to find the information they were looking for, perhaps repeatedly navigating between the same pages without success. Both behaviors produce a long session, but require opposite interpretations and interventions.
Cross-referencing session duration with other behavioral signals, such as scroll depth (how much of the page is actually seen), number of pages visited in the session, and final conversion rate, allows distinguishing long sessions of real interest from long sessions of navigational frustration.
Anti-patterns
Common mistake: automatically interpreting a growing session duration as a positive engagement signal, without checking whether it corresponds to increased scroll depth and conversions or increased frustrated navigation between pages.
Second mistake: worrying about short sessions on B2B conversion pages, when they often reflect visitors already informed by prior research or referral, converting quickly precisely because the decision journey was already mature before the visit.
Practical Application
A company observes an average session duration increase from 2:10 to 4:40 minutes on its product page and interprets it as improved engagement. Analyzing scroll depth, it discovers the additional time is spent repeatedly navigating between the product page and the FAQ page, never reaching the pricing section: after moving pricing information higher on the page, session duration drops to 3:00 minutes but contact requests rise 28%.