If your study is performing well and you want to collect more data, you can increase the target sample size without stopping the study. This feature allows you to seamlessly expand your research while maintaining the momentum of an active study.
When to Increase Sample Size
Consider increasing your target sample size in these situations:
Study Performance Indicators
- High completion rates: Participants are engaging well with your study
- Good data quality: Responses are thoughtful and complete
- Fast recruitment: You're reaching your target faster than expected
- Positive feedback: Participants are providing good reviews
Research Considerations
- Statistical power: More participants would strengthen your findings
- Effect sizes: Initial data suggests you need larger sample for precision
- Subgroup analysis: Want adequate sample sizes for different participant groups
- Replication confidence: Larger sample increases confidence in results
Budget and Timeline
- Additional budget available: You have extra research funds
- Time permits: Your research timeline allows for more data collection
- Cost efficiency: Current cost per participant is favorable
💡 Optimal Timing
The best time to increase sample size is when your study is performing well but hasn't yet reached the original target. This maintains recruitment momentum while expanding your dataset.
How to Increase Sample Size
The process is straightforward but requires adequate funding:
Step-by-Step Process
- Navigate to your active study's management page
- Look for the "Sample Size" or "Target Participants" field
- Click to edit the sample size field
- Enter the new, higher target number
- Review the updated cost calculation
- Check your wallet balance status
- Add funds if prompted
- Save the changes
Automatic Cost Calculation
When you increase the sample size, the system will:
- Calculate the additional cost for new participants
- Show you exactly how much extra funding is needed
- Display the new total study cost
- Update service fee calculations automatically
Funding Requirements
Automatic Fund Check
The system performs an immediate wallet balance check:
- Sufficient funds: Change is saved immediately
- Insufficient funds: You'll be prompted to add more funds
- Exact amount needed: System shows precise funding gap
Adding Additional Funds
If your wallet needs a top-up:
- Click the "Add Funds" button when prompted
- The system suggests the exact amount needed
- Choose your payment method
- Complete the funding transaction
- Return to save your sample size increase
⚠️ Cannot Save Without Funds
You cannot save the sample size increase until your wallet has sufficient funds to cover the additional participants. The change will be blocked until funding is complete.
What Happens After Increasing
Immediate Effects
- Recruitment continues: System continues inviting until new target is met
- Progress tracking: Dashboard updates to show new target
- Funds reserved: Additional funds are immediately reserved
- Timeline extends: Study may run longer to reach new target
Participant Experience
- New participants see the same study as before
- No changes to study content or compensation
- Invitation process continues seamlessly
- Study remains equally appealing to new participants
Data Collection Impact
- Continuous data: New data integrates with existing responses
- Consistent methodology: No methodological breaks in data collection
- Timeline considerations: Longer collection period may introduce temporal effects
Cost Calculation Example
Understanding the financial impact:
📊 Example Scenario
Original study: 100 participants at $3.00 each = $300
Service fee (15%): $45
Original total: $345
Increase to: 150 participants
Additional participants: 50
Additional cost: 50 × $3.00 = $150
Additional service fee: $150 × 15% = $22.50
Total additional funding needed: $172.50
Strategic Considerations
Timing the Increase
- Early increase: Maximum benefit from extended recruitment
- Mid-study increase: Based on performance data
- Late increase: May extend study significantly
Sample Size Planning
- Statistical planning: Consider power analysis for new target
- Incremental increases: Can increase multiple times if needed
- Budget planning: Ensure adequate funds for full increase
Quality vs. Quantity
- Monitor quality: Ensure larger sample doesn't reduce quality
- Recruitment fatigue: Watch for declining completion rates
- Timeline impact: Longer studies may affect participant behavior
Best Practices
Before Increasing
- Review current data quality and completion rates
- Confirm budget availability for the increase
- Consider impact on research timeline
- Plan for extended monitoring responsibilities
After Increasing
- Continue monitoring data quality with larger sample
- Track completion rates for any changes
- Update research documentation with new target
- Monitor timeline to completion
Important
You can increase the sample size multiple times during a study, but each increase requires additional funding. Plan your increases strategically to avoid excessive fund reservations and to maintain study quality.
Monitoring Increased Studies
Dashboard Updates
- Progress bars reflect new target numbers
- Completion percentages recalculate automatically
- Timeline projections update based on current rate
- Cost tracking includes all increases
Performance Tracking
- Monitor if completion rates remain consistent
- Track recruitment speed after increases
- Watch for any changes in data quality patterns
- Compare pre- and post-increase participant behavior
Troubleshooting
Cannot Increase Sample Size
- Study status: Must be in
STARTEDstatus - Insufficient funds: Add funds to wallet first
- System limits: Very large increases may require approval
Slow Recruitment After Increase
- Check if eligible participant pool is depleted
- Consider adjusting participant filters
- Review if compensation remains competitive
- Evaluate study appeal and description