Avg Replay Duration, PostHog

Avg Replay Duration for PostHog stores. Tracked live in Vortex IQ Nerve Centre. How to read it, why it matters, and how to act on it.

Metrics type: Supporting Metrics • Category: Analytics

At a glance

Avg Replay Duration is a session-replay metric tracked from PostHog data. It measures the average length of the session recordings PostHog captures. Replay length is a quiet proxy for engagement and for how much there is to review: longer replays often mean deeper sessions, while a sudden shift, very short or unusually long, can point to a capture issue or a UX change worth watching on the recordings themselves.

What it counts	The average duration of captured session replays for the period.
Sample type	Backend API data from PostHog session-replay recordings, refreshed on the standard data refresh.
Why it matters	Replay length frames how much behaviour each recording holds. Tracking it helps you spot engagement shifts and capture anomalies before you start watching sessions.
Reading the value	Compare the current period against the prior period. A sharp change in either direction is worth investigating on the replays.
Currency	count
Time window	30D vsP
Alert trigger	-
Sentiment key	ph_replay_avg_duration
Roles	owner, marketing

Calculation

Calculated automatically from your PostHog data. See the At a glance summary above for what the metric tracks and the worked example below for a typical reading.

Worked example

A representative reading of Avg Replay Duration for a typical merchant on PostHog. Suppose captured replays average about 2 minutes 40 seconds. After a homepage redesign on 18 May 26, the average jumps to 4 minutes 10 seconds. Longer replays could mean richer engagement or could mean users hunting for something they used to find easily. The card flags the shift; the replays themselves tell the story. Cross-reference Replays Containing Rage Clicks to check whether the longer sessions are frustrated ones. For deeper investigation, use Vortex Mind to trace upstream causes; for natural-language exploration, ask Ask Viq.

Sibling cards merchants should reference together

Card	Why merchants reach for it
ph_replays_with_rage_clicks	Session Replay sibling: frustrated sessions.
ph_session_replay_count	Session Replay sibling: how many replays were captured.
ph_session_replay_coverage	Session Replay sibling: capture coverage.
pos_avg_session_duration	Engagement sibling: average session length.
pos_sessions	Audience sibling: total sessions.

Reconciling against the vendor’s own dashboard

Where to look in PostHog’s own dashboard:

In PostHog, open Session Replay. Each recording lists its duration, and the list can be sorted and filtered. The average across the period should align with this card. Note that PostHog can trim or cap recordings, which affects the average.

Why the Vortex IQ value may legitimately differ:

Reason	Direction	What to do
Recording caps. PostHog may cap maximum recording length, truncating long sessions.	Variable	Account for the cap.
Sampling. If replay sampling is on, the captured set is a subset of sessions.	Variable	Confirm the sampling rate.
Idle handling. How idle time is counted in a recording shifts the average.	Variable	Check the idle settings.

Cross-connector reconciliation: complement with sibling cards in the same category for the full diagnostic picture. For divergence investigations, use Vortex Mind.

Known limitations / merchant FAQs

Q: How often does Avg Replay Duration update? The card refreshes on the standard data refresh (typically every 30-60 minutes for live integrations). For real-time signals, force a manual refresh from the dashboard.

Q: Is a longer replay better? Not necessarily. Longer can mean deeper engagement or it can mean users struggling to find something. Read it alongside rage clicks and conversion before concluding.

Q: Why is replay duration different from session duration? Replay duration measures the recorded portion of a session, which can be capped or sampled. Session duration measures the full session from events. The two are related but not identical.

Q: Can I customise the alert threshold? Yes, alert thresholds are configurable per profile in the Alert Rules tab. Adjust to match your business baseline rather than relying on the generic default.

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Tracked live in Vortex IQ Nerve Centre

Avg Replay Duration is one of hundreds of KPI pulses Vortex IQ tracks across PostHog and 70+ other ecommerce connectors. Nerve Centre runs the detection layer; Vortex Mind investigates the cause when something moves; Ask Viq lets you interrogate any number in plain English.

Start for free or book a demo to see this metric running on your own data.