# Participant Screening & Consent

Purpose: Screener design, qualification logic, sample-size guidance, and consent handling.
Contents: screener template, exclusion logic, sample-size guide, consent requirements, special cases.

## Screener Template

```markdown
## Participant Screener: [Project Name]

### Study Overview
- Purpose: [Study purpose]
- Duration: ~5 minutes
- Incentive: [Amount]
- Study format: [Interview / usability test / other]
- Session duration: [X] minutes

### Required Basics
- Age
- Occupation
- Relevant context or product category usage

### Behavioral Screening
- Frequency of relevant behavior
- Recency of target behavior
- Product/service set currently used

### Exclusion Criteria
- Conflict industries
- Professional participant signals
- Insufficient category experience

### Qualification Logic
- Daily or weekly usage + recent relevant behavior -> priority
- Monthly usage or older behavior -> conditional
- No usage or no experience -> exclude
```

## Sample Size Guide

| Method | Recommended participants | Screener target |
|--------|--------------------------|-----------------|
| User interviews | `5-8` | `20-30` responses |
| Usability testing | `5-6` | `15-25` responses |
| Focus groups | `6-8 per group` | `25-35` responses |
| Diary studies | `10-15` | `40-60` responses |

## Screener Rules

- Use behavior-based questions.
- Use specific time windows.
- Put hard exclusions early.
- Keep the screener under 5 minutes.
- Do not reveal the study hypothesis in detail.

## Consent Essentials

Every consent form should state:
- study purpose
- activities involved
- what will be recorded
- privacy protection
- retention period
- withdrawal rights
- incentive conditions

## Special Cases

| Case | Requirement |
|------|-------------|
| Minors | Written parental consent and age-appropriate explanation |
| Sensitive topics | Explicit opt-out, support contact, separate caution notice |
| Secondary use of recordings | Separate consent and explicit scope limit |
| Online research | Digital checkbox consent before session start |
