Period comparison

The "Compare" pill at the top of the dashboard turns on automatic comparison: each KPI and each curve shows its change against a reference window.

#Three modes

• None (default) — no delta, no compare tooltip.
• Previous period — the window of the same length immediately before the active period.
• Previous year (YoY) — the same window, exactly one year earlier.

#Examples — previous period

• Period = 30 days → compared to the previous 30 days.
• Period = March 1 → 15 → compared to February 14 → 28.
• Period = 24h → compared to the previous 24h.

#Examples — previous year (YoY)

• Period = March 1 → 15, 2026 → compared to March 1 → 15, 2025.
• Period = last 7 days → compared to the same rolling week one year earlier.

YoY relies exclusively on the long-term aggregates (25-month retention). The hour granularity is disabled with YoY — raw events from a year ago no longer exist.

#Reading

• A green arrow signals an improvement (more visits, longer duration, lower error rate, etc.).
• A red arrow signals a regression.
• A grey dash signals a negligible change (< 5%).

The polarity (positive vs negative) depends on the metric: for traffic KPIs, more = better; for 500 errors or abnormally short durations, less = better.

#Compare tooltips

On ranking tables (top pages, top countries, etc.) and on the KPIs, hovering a value shows the reference value plus absolute and relative delta. The tooltip only appears if a compare mode is active and a reference value exists.

#Limits

• Previous period comparison: works on aggregates (25 months); raw data (drill-down) caps at 90 days.
• YoY comparison: aggregates only, hour granularity unavailable, year_ago is null if the site didn't exist a year ago (the comparison is then hidden).
• If the reference window holds no data, the KPI renders without an arrow and the tooltip reads "no comparable data".