---
slug: vergleich-vorperiode
title: "Why is there no comparison with the previous period?"
category: berichte
locale: en
updated: 2026-09-30
keywords: ["previous period","comparison","last month","percentage","measurement start","overview"]
questions: ["Why does my overview show no percentage change compared with the previous period?","Why are the percentages missing on the overview?","What does “previous period incomplete” mean?","Why does the overview show several hundred per cent growth?","When will I see a comparison with last month?","When did my measurement start?","Why does the notification not report a drop?"]
url: https://bench.metrunio.com/en/help/vergleich-vorperiode
---

# Why is there no comparison with the previous period?

**Why does my overview show no percentage change compared with the previous period?**

The comparison is only made with a previous period that is fully measured. If it starts before your measurement start, you see “Previous period incomplete” instead of a comparison. The measurement start is the first contact Metrunio measured live (in the browser, on an ad or through the server API); imported orders and ad spend do not count towards it.

Every tile on the overview compares the selected period with the period of the same length right before it: 30 days with the 30 days before. That only holds if both are measured. If part of the previous period lies before your measurement, there are hardly any contacts in it, and almost every figure seems to grow by hundreds of per cent. That would be the start of measurement, not a development. So there is no comparison then, but a sentence with the measurement start and the dates of the previous period.

## What counts as the measurement start

- The earliest contact Metrunio measured live: in the browser (tracking snippet, Shopify app), on an ad (impression pixel, viewability tag, click redirect) or through the server API. Like the snippet, it reaches back 30 days at most.
- Not imported orders: an import of order history brings earlier purchases, but not a single contact they could be attributed to.
- Not ad spend: it is not a contact and may reach back a long way.
- When the retention period ends, the measurement start moves with it: what has been deleted cannot be compared.

## When the comparison appears

As soon as the previous period lies entirely after the measurement start: for 7 days two weeks after the first contact, for 30 days after two months, for 90 days after half a year. A shorter period therefore shows the comparison sooner.

## Where the same rule applies

- Notifications about a sharp change compare seven days with the seven before. As long as the previous week lies before the measurement start, they report nothing.
- The figures the assistant reads under “Ask your data” and the read API (`/v1/data/overview`) state the measurement start (`measurement.since`) and whether the period is fully measured (`measurement.complete`).

> **Note:** The demo’s example data loads regular customers and ad spend long before its first contact. There, too, 30 days show no comparison, while 7 days do.

## Also asked

- Why are the percentages missing on the overview?
- What does “previous period incomplete” mean?
- Why does the overview show several hundred per cent growth?
- When will I see a comparison with last month?
- When did my measurement start?
- Why does the notification not report a drop?

## Related

- https://bench.metrunio.com/en/help/berichte-ueberblick
- https://bench.metrunio.com/en/help/roas-und-kennzahlen
- https://bench.metrunio.com/en/help/shopify-app
- https://bench.metrunio.com/en/help/aufbewahrung
- https://bench.metrunio.com/en/help/demo-ansehen