How to compare sales cohorts with open opportunities

01

Choose the start and cutoff

Define a cohort as distinct opportunities entering the same starting stage in a specified period. Record the stage definition, entry date and first confirmed sale date. Choose a fixed window that reflects the buying cycle, such as 90 days after each opportunity enters the stage. An opportunity that has not had the full window is immature for that comparison.

Use the same rules for duplicates, reopened records and skipped stages across groups. If a person has two separate purchasing decisions, decide whether each is a distinct opportunity before counting. Store open, lost and won outcomes at the cutoff. An opportunity open on day 90 may still become a sale later.

A conversion rate is sales within the window divided by all eligible opportunities in the starting cohort. It describes that window, not lifetime conversion. Report the number of records behind the percentage, and do not remove open cases from the denominator simply because their outcome is unresolved.

02

Compare groups at the same age

Suppose 100 opportunities enter qualification in January and another 100 enter in April. At 90 days after each entry, January has 20 sales, 50 losses and 30 open. April has 16 sales, 44 losses and 40 open. The observed 90-day conversion rates are 20% and 16%. The open shares are 30% and 40%. They show that many outcomes remain unresolved at the cutoff.

The four-point difference does not establish why the cohorts differ. April may have more long-cycle opportunities, a different offer or later-entered records. Check the mix, stage definitions and timestamps, then inspect a sample of open and lost cases. Do not add later sales to only one cohort or call all open opportunities losses.

If the April cohort has only reached day 60, either wait for its 90-day window or compare both cohorts at day 60. Label the shorter view and retain a later review date. Small cohorts can change materially with one additional sale.

03

Use the open queue

For each open opportunity, record an owner, last meaningful interaction, agreed next action and date. Check whether a stale stage reflects an unresolved customer decision or simply a missing update. Close records only when evidence supports the outcome, and keep a history if they reopen.

Before any follow-up, check channel permission, contact preferences, suppression and applicable rules in the recipient's jurisdiction. Review the cohort again at a longer, common window if the buying cycle warrants it. Compare the count and value of sales as well as conversion rate, and note that a later comparison still does not prove which change caused the result.