# Use fixed keyword cohorts for comparable ASO trends

URL: https://storelift.net/guide/fixed-keyword-cohort-report/
Language: en
Updated: 2026-10-02

A portfolio average changes when ranks move, but also when terms are added or removed. A fixed cohort holds the tracked population steady so that a trend is easier to interpret. Keep a second view for newly discovered terms rather than silently merging the two.

## Investigation steps

1. Define membership using app, platform, country and exact term. Save the cohort date and keep this membership unchanged throughout the comparison window.
2. For each period, report successful observations, outside-range results and failed measurements. Changing data coverage can alter the average even with fixed membership.
3. Show individual movers beside the cohort summary. A single large move can dominate a small set; the distribution is often more useful than one mean.

## Worked interpretation

Illustrative case: five new terms enter tracking at rank 80 while the original twenty terms stay unchanged. The whole portfolio average worsens, but the fixed twenty-term cohort is stable. Both statements can be true.

## Decision and next check

Maintain one view for progress on the established set and another for expansion. When a cohort needs to change, start a new version and preserve the earlier membership. Explain the break in the report instead of presenting unlike populations as a continuous trend.

## Related Storelift feature

Read App rank tracker for the available product data and its scope. Keep the app, storefront, period and measurement status with the observations used in your report.