Review whether another interview round will help
Replace a fixed interview target with an explicit review of new information, sample variation, and unresolved evidence.
- Preparation
- A review after each interview round
- Difficulty
- Advanced
- Task
- Decide whether to interview again
Before you start
Get what you need before you start
- State the research question, sample definition, and decision the research informs.
- Prepare verified findings by interview round.
Steps
Work through the method
Use the listed inputs and tools. Check the evidence when you need to verify a step.
Define useful new information
Describe which new theme, variation, contrary case, or missing context could change the decision.
Why it matters: A sufficiency review needs a question-specific test.
- Input
- The research question and pending decision.
- Output
- A written new-information rule.
Tools in this stepGoogle SheetsEvidence for this step
Thematic saturation depends on the research question, sample, and analysis method rather than a universal interview count.
PLOS ONE via PubMed Central: A brief history of saturation and qualitative sample size estimation; Discussion
Review evidence by round
For each interview round, list newly supported themes, repeated themes, contrary cases, and corrected interpretations.
Why it matters: Round-level review shows whether new interviews change the current account.
- Input
- Verified findings grouped by round.
- Output
- A round comparison.
Tools in this stepGoogle SheetsEvidence for this step
Thematic saturation depends on the research question, sample, and analysis method rather than a universal interview count.
PLOS ONE via PubMed Central: A brief history of saturation and qualitative sample size estimation; DiscussionVanta’s founder describes continuing interviews until much of a new account became predictable.
First Round Review: Zeroing in on the Right Problem to Pursue, stopping heuristic
Inspect sample variation
Check whether missing segments, contexts, or experiences could introduce information relevant to the decision.
Why it matters: Repeated accounts from one narrow sample may leave a material gap.
- Input
- The sample definition and participant mix.
- Output
- A sample-gap note.
Tools in this stepGoogle SheetsEvidence for this step
Thematic saturation depends on the research question, sample, and analysis method rather than a universal interview count.
PLOS ONE via PubMed Central: A brief history of saturation and qualitative sample size estimation; Discussion
Track contrary cases
Review evidence that weakens the current themes and state whether another participant group could test it.
Why it matters: Contrary evidence can matter even when common themes repeat.
- Input
- The round comparison and tested themes.
- Output
- A contrary-case review.
Tools in this stepGoogle SheetsEvidence for this step
A practitioner recommends preserving transcripts and pressure-testing early themes before choosing a solution.
First Round Review: FIGURING OUT WHAT TO GO AFTER; Mistake #1: Chasing themes
Choose stop, continue, or change sample
Document the route and connect it to the new-information rule, sample gaps, and contrary cases.
Why it matters: The decision should follow the observed evidence rather than a universal count.
- Input
- The completed sufficiency review.
- Output
- A documented research-route decision.
Tools in this stepGoogle SheetsEvidence for this step
Thematic saturation depends on the research question, sample, and analysis method rather than a universal interview count.
PLOS ONE via PubMed Central: A brief history of saturation and qualitative sample size estimation; DiscussionServal’s founder describes continuing discovery until patterns appeared and changing the question when buyers did not call solved work painful.
First Round Review: The customer discovery breakthrough
State the remaining limit
Record what the research still cannot establish about the customer, market, or venture decision.
Why it matters: Stopping interviews does not prove product-market fit or a complete account.
- Input
- The research-route decision.
- Output
- A limit statement for the decision record.
Tools in this stepGoogle SheetsEvidence for this step
Vanta’s founder describes continuing interviews until much of a new account became predictable.
First Round Review: Zeroing in on the Right Problem to Pursue, stopping heuristicServal’s founder describes continuing discovery until patterns appeared and changing the question when buyers did not call solved work painful.
First Round Review: The customer discovery breakthrough
Success checks
Check the result before you finish
- The decision uses a question-specific new-information rule.
- Sample gaps and contrary cases remain visible.
- No universal interview count appears in the decision.
Failure modes
Watch for these problems
- Change the sample when repetition comes from a narrow participant group.
- Continue when a named unresolved gap could change the decision.
- Request specialist review before presenting thematic saturation as a formal research conclusion.
Tools
Choose the tools you need
Tool
Google Sheets
A shared spreadsheet for source-linked research, decisions, and operating records that people can inspect and correct.
Check fit, limits and pricingSources
Read the sources behind this practice
Check what each source supports and where the advice has limits.
- PLOS ONE via PubMed Central: A simple method to assess and report thematic saturation in qualitative researchPeer-reviewed research paper · Publication date unavailable
- First Round Review: Vanta's Path to Product-Market FitEdited founder interview · Publication date unavailable
- First Round Review: Serval's Path to Product-Market FitEdited founder interview · Publication date unavailable
- First Round Review: A UX Research Crash Course for FoundersEdited practitioner interview · Publication date unavailable
- Google Workspace: Collaborative, AI-powered spreadsheetsOfficial product page · Publication date unavailable