How to recruit research participants who can change what you learn.

1. Start with the experience that matters.

Write your research question before writing an invitation. If you need to understand how newcomers prepared for a first session, recent first-time participants are relevant in a way that long-standing organisers may not be. If you are investigating an unfinished task, people who abandoned it may know something that completed registrations cannot explain. The relevant experience should determine the brief, not the size of an existing mailing list.

Describe the experience in terms a person can recognise. Avoid requiring someone to agree that your proposed solution would help before they can participate. That would filter for your conclusion. Also distinguish a task condition from a personal characteristic. Ask only for information that helps answer the question or arrange participation; a detailed biography is not a substitute for a clear reason to include somebody.

2. Write criteria, exclusions, and missing perspectives.

GOV.UK's participant guidance emphasises actual or likely users and attention to different access needs. Use that as a starting boundary, then explain your own selection decisions. Record which experience is required, which differences you want to explore, and any condition that makes the proposed session inappropriate. Keep the reason beside each criterion so a convenient restriction cannot quietly become a claim about the audience.

Maintain a missing-perspectives line from the beginning. A session offered only during working hours may miss people whose schedules differ. A web-only invitation may miss those who rely on another person or channel. You may not resolve every gap in one round, but you can stop the report from saying users when it really means people who saw this invitation and could attend under these conditions.

3. Choose recruitment channels that fit the question.

Compare channels for the experience you need, not just response speed. An opt-in invitation to recent participants might suit a preparation question; an approved community notice might reach people who have never registered. A gatekeeper's opinion can help you understand the setting, but it is not automatically an account from the people using the service. Keep the two source types separate.

Ask permission before posting in a group or approaching people through an organisation. Describe the research accurately and make declining uncomplicated. If a colleague helps arrange introductions, agree what information is actually necessary to share. Do not add people to a marketing list because they expressed research interest, and do not imply that giving a positive answer is the price of being helpful.

4. Make participation understandable before scheduling.

Draft a plain invitation with the purpose, activity, expected commitment, contact method, and how to ask questions or decline. State whether the session concerns a prototype or a working service. Explain any planned recording and who would see the material through your agreed information and consent process. This worksheet helps you notice those decisions; filling it in does not itself establish informed consent.

Ask about participation arrangements in a way that does not demand an unnecessary diagnosis or personal history. A person might need a different format, communication method, device setup, or time. Arrange what you can support before confirming the session. If compensation or expenses are offered, state the terms through the appropriate process and do not make favourable feedback a condition. Keep the invitation separate from a request for a testimonial.

5. Work through a hypothetical recruitment brief.

Imagine a team trying to understand confusing arrival information for a community workshop. This is a hypothetical example, not a SIX33 study. The first draft asks enthusiastic supporters to review our improved welcome page. That wording selects for goodwill and points attention toward the proposed page before establishing how people prepared for the session.

A better brief names adults who recently prepared to attend for the first time, including people who asked for clarification or did not complete the arrival process where an appropriate invitation route exists. The question is how they found the time, place, and contact information. Prior experience with the team and the channel used for preparation are context to record, not reasons to manufacture a balanced-looking group.

Suppose the eventual sessions include only people who successfully arrived after a direct message from the coordinator. The team can learn from those experiences, but it cannot describe the findings as the experience of every newcomer or of people who never reached the venue. The next recruitment decision might deliberately seek a different preparation route. The useful output is a visible limitation and a better next question, not an unsupported claim of representativeness.

6. Review who took part, not just how many.

Before the first session, check the achieved group against the question and the participation arrangements. Keep a cancellation or non-response as a recruitment status, not an opinion about the service. A person who did not reply has not rejected your idea. If a criterion changes, record the reason and the version of the brief so the final account can explain how the group was assembled.

Afterward, report the channels, relevant experience, exclusions, and gaps alongside the session count. Avoid presenting a convenience group as a population estimate. The method and question determine what further research is appropriate; there is no universal participant number that certifies a need, a product, or an impact claim. Repeated sessions with highly familiar people may answer a different question from a first encounter.

Finally, follow the agreed handling and retention arrangements for contact and screening material. Keep the recruitment record separate from public findings, using private source pointers where needed. A public report usually needs to explain why a participant's experience was relevant, not reveal who they are. Recruitment has done useful work when it makes the eventual claim narrower, clearer, and more open to being challenged.