02. Write eligibility, recruitment and repeat-contact procedures
Lesson
LEARNING OBJECTIVES
Write recruitment rules that field staff can apply consistently, record participant flow, and distinguish non-response from ineligibility or missing data.
STANDARDIZE THE CONTACT PROCESS
A recruitment procedure should identify the selected unit, how it is located, how eligibility is assessed, how an eligible person is selected when there are several, what information is provided, and what is recorded after each attempt. Include safe and respectful contact arrangements suited to the setting.
Do not replace the random selection rule with whoever is available. Do not allow a gatekeeper to decide which eligible people are most cooperative. Define how household lists are updated and how an address that cannot be located is investigated.
Use distinct outcome codes: not yet contacted, eligibility unresolved, ineligible, eligible and declined, eligible and unavailable, consented, partially completed and completed, for example. Adapt these categories to the actual study rather than claiming one universal response-rate denominator.
WORKED FICTIONAL CONTACT HISTORY
Household H014 was selected from the frame. On the first visit no caregiver was available; a prespecified later contact was arranged. At the second visit two eligible children were listed and one was randomly selected using the approved method. The caregiver received the study information and declined.
Record the attempts, eligibility assessment, selection process and decline without collecting unnecessary reasons or identifying information. Do not replace H014 with a nearby consenting household unless the sampling protocol explicitly provides a defensible mechanism reviewed for its consequences.
Another household completes the questionnaire but skips an outcome item. This is item non-response, not the same as a household refusing participation. Keep these processes distinguishable for analysis and reporting.
PLAN PARTICIPANT FLOW
Keep counts of selected units, contacts, eligibility outcomes, consent, completed interviews, partial interviews and analysis inclusion. Specify who reconciles discrepancies and how privacy is protected. For subgroup response summaries, use available permitted information and avoid making unsupported assumptions about non-respondents.
YOUR TASK
Write a one-page standard operating procedure for initial contact, eligibility checks, within-household selection, repeat contacts and refusal. Add a small fictional contact log with five different outcomes.
Review whether interviewers can identify the next step without improvising. Specify escalation for inaccessible areas, suspected duplicates or eligibility ambiguities, and how deviations are documented. Do not insert a fixed number of attempts merely because it appears in an example; justify your own plan.
SELF-CHECK AND FEEDBACK
1. Is failure to find someone at home evidence of refusal? No; record the observed contact outcome.
2. Is an unanswered item a meaningful zero? No; apply the declared missing-data rule.
3. Can an overall response percentage reveal all selection problems? No; examine the frame, contact process and patterns of participation.
PORTFOLIO OUTPUT
A recruitment SOP, eligibility decision rules, a fictional contact log and a participant-flow outline.
FURTHER READING
WHO STEPS Manual.
https://www.who.int/docs/default-source/ncds/ncd-surveillance/steps/part2.pdf
CDC Field Epidemiology Manual: Collecting Data.
https://www.cdc.gov/field-epi-manual/php/chapters/collecting-data.html
Write recruitment rules that field staff can apply consistently, record participant flow, and distinguish non-response from ineligibility or missing data.
STANDARDIZE THE CONTACT PROCESS
A recruitment procedure should identify the selected unit, how it is located, how eligibility is assessed, how an eligible person is selected when there are several, what information is provided, and what is recorded after each attempt. Include safe and respectful contact arrangements suited to the setting.
Do not replace the random selection rule with whoever is available. Do not allow a gatekeeper to decide which eligible people are most cooperative. Define how household lists are updated and how an address that cannot be located is investigated.
Use distinct outcome codes: not yet contacted, eligibility unresolved, ineligible, eligible and declined, eligible and unavailable, consented, partially completed and completed, for example. Adapt these categories to the actual study rather than claiming one universal response-rate denominator.
WORKED FICTIONAL CONTACT HISTORY
Household H014 was selected from the frame. On the first visit no caregiver was available; a prespecified later contact was arranged. At the second visit two eligible children were listed and one was randomly selected using the approved method. The caregiver received the study information and declined.
Record the attempts, eligibility assessment, selection process and decline without collecting unnecessary reasons or identifying information. Do not replace H014 with a nearby consenting household unless the sampling protocol explicitly provides a defensible mechanism reviewed for its consequences.
Another household completes the questionnaire but skips an outcome item. This is item non-response, not the same as a household refusing participation. Keep these processes distinguishable for analysis and reporting.
PLAN PARTICIPANT FLOW
Keep counts of selected units, contacts, eligibility outcomes, consent, completed interviews, partial interviews and analysis inclusion. Specify who reconciles discrepancies and how privacy is protected. For subgroup response summaries, use available permitted information and avoid making unsupported assumptions about non-respondents.
YOUR TASK
Write a one-page standard operating procedure for initial contact, eligibility checks, within-household selection, repeat contacts and refusal. Add a small fictional contact log with five different outcomes.
Review whether interviewers can identify the next step without improvising. Specify escalation for inaccessible areas, suspected duplicates or eligibility ambiguities, and how deviations are documented. Do not insert a fixed number of attempts merely because it appears in an example; justify your own plan.
SELF-CHECK AND FEEDBACK
1. Is failure to find someone at home evidence of refusal? No; record the observed contact outcome.
2. Is an unanswered item a meaningful zero? No; apply the declared missing-data rule.
3. Can an overall response percentage reveal all selection problems? No; examine the frame, contact process and patterns of participation.
PORTFOLIO OUTPUT
A recruitment SOP, eligibility decision rules, a fictional contact log and a participant-flow outline.
FURTHER READING
WHO STEPS Manual.
https://www.who.int/docs/default-source/ncds/ncd-surveillance/steps/part2.pdf
CDC Field Epidemiology Manual: Collecting Data.
https://www.cdc.gov/field-epi-manual/php/chapters/collecting-data.html
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