How to Recruit Participants for a Card Sort Study
You've built your study. Now you need people to take it.
Getting responses is the most common sticking point for UX researchers running card sorts. This guide covers every recruitment method — from free to paid — so you can find the right participants for your research.
Why Recruitment Matters More Than You Think
Card sorting is only as good as the people who take it. Recruiting the wrong participants (e.g., your colleagues when you're designing for customers) produces misleading patterns. Recruiting too few means your similarity matrix won't show reliable groupings.
The good news: you don't need hundreds of people. You need the right people.
Method 1: Your Existing Users (Free, High Quality)
If you have an existing product or website, your own users are your best source of participants. They represent your actual audience and will sort cards based on their real mental models.
How to reach them:
- Send a brief email to your user list with a one-line ask: "We're improving our navigation — would you spend 5 minutes sorting some cards?"
- Add a banner or in-app message to your product pointing to the study link
- Post in your user community or Slack group
What works: Offering a small incentive (a discount, gift card, or early access to a feature) can 3–5x your response rate.
Realistic output: 20–50 responses from a list of 500–1,000 users, depending on your relationship with them.
Method 2: Colleagues and Teammates (Free, Fast)
For internal tools, intranets, or early-stage products, teammates are a legitimate participant pool — as long as they represent the actual users.
How to reach them:
- Post the link in your company Slack (#general or relevant team channels)
- Send a direct message to 10–15 people asking for 5 minutes of their time
- Present it at a team meeting as a quick in-session activity
Caveat: Don't use colleagues for consumer-facing products where they'd have different mental models than your customers. The patterns will look cleaner than reality.
Method 3: Social Networks (Free, Variable Quality)
Posting your card sort link publicly can get you responses quickly — but the quality depends heavily on who sees it.
Where to post:
- LinkedIn: Frame it as a UX research project and ask your network for help
- Twitter/X: Include the study link with a brief explanation of what you're researching
- Reddit: Subreddits like r/userexperience, r/webdesign, or domain-specific communities (e.g., r/personalfinance for a fintech app)
- Facebook groups relevant to your topic area
What to expect: 10–30 responses from a LinkedIn post with ~500 connections. Reddit can drive spikes of 30–50 responses if the post resonates.
Method 4: Prolific Research Panel (Paid, Best Quality)
Prolific is a platform specifically designed for academic and UX research. Participants are pre-screened and motivated to complete studies carefully — the response quality is noticeably higher than general crowdsourcing platforms.
Why Prolific works well for card sorting:
- Participants are used to research tasks and understand the format
- You can filter by demographics: country, age, employment, domain expertise
- Average completion rates are 90%+
- Studies complete in hours, not days
Cost: Typically ~$1.50–$2.50 per response (participant reward + Prolific's service fee). A 20-person study costs around $40–60.
How to use it with FreeCardSort: Prolific recruitment is built directly into FreeCardSort. From your study dashboard, click "Recruit with Prolific," set your target number of participants and reward, and launch. Responses start appearing within minutes.
Learn more about the Prolific integration →
Method 5: UserTesting and Similar Panels (Paid, Premium)
Platforms like UserTesting offer access to large research panels but at significantly higher cost ($30–$100+ per participant). For card sorting — a relatively short, low-complexity task — this price premium usually isn't justified.
Prolific or your own users will give you equivalent or better results for less money.
Method 6: Research Agencies (Paid, Specialist)
If you need highly specific participants (e.g., ICU nurses, hedge fund managers, or rare specialist roles), a research recruitment agency may be your only option. Expect to pay $50–$150+ per participant and allow 1–2 weeks for recruitment.
This is overkill for most card sorts. Start with Prolific's demographic filters — they cover a surprisingly wide range of professional profiles.
How Many Participants Do You Need?
As a rule of thumb:
| Goal | Minimum participants |
|---|---|
| Pilot test / check your study setup | 5 |
| Identify basic patterns | 15–20 |
| Reliable similarity matrix | 20–30 |
| Publishable / high-confidence results | 30–50 |
More detail: How many participants do you need for card sorting? →
Practical Tips
Send reminders. If you've shared a link via email or Slack, a single follow-up 3–5 days later typically doubles your response count.
Make the time commitment clear. "Takes about 5 minutes" in your recruitment message meaningfully increases completion rates versus just sharing a link.
Use AI responses first. FreeCardSort's AI-generated responses let you populate your results with realistic test data before you have real participants. Use this to check that your study layout makes sense and your cards are clear before recruiting.
Close your study once you have enough. Once you hit 20–30 responses, the patterns generally stabilize. Running to 100+ rarely changes the conclusions but costs significantly more.
Quick Recruitment Checklist
- Study is live and tested (use AI responses first)
- Study link is easy to share (short, no login required for participants)
- Recruitment message includes time estimate ("5 minutes")
- Participants match your actual target audience
- Incentive considered (even a simple thank-you message helps)
- Follow-up reminder scheduled for 3–5 days after initial ask
Ready to recruit? Create your card sort study →