# Board metrics

Headlines are rebuilt from stored events. Tiles stay 0 or — until those events exist. Zarstat does not invent visitors, sessions, or rand.

## Sessions

A session is a run of events on the same first-party visitor_id with no gap longer than 30 minutes. The board uses that gap, not the tab sessionStorage id.

## Bounce rate

Sessions with exactly one pageview, divided by sessions. No sessions → —.

## Conversion rate

Visitors with at least one purchase, divided by visitors. No visitors → —. Amount is rand, not cents.

## Avg session duration

First event to last event in each session, in seconds, then the mean. A single-event session is 0 seconds.

## New vs returning

Returning means that visitor_id was seen before the start of the selected 7d or 30d window. All-time has no prior window, so everyone is new. This is first-party localStorage, not a cookie.

## Pageviews

Count of stored pageview events. Visitors / ZAR / RPV stay the pin-able #1 KPIs.

HTML twin: https://www.zarstat.co.za/docs/metrics