We ran a test, five versions of a fundraising letter.  Each one told the same story about the same woman — her loss of sight, her journey to get it back, and how donors made it possible.  What changed?

The way the story was told was tailored to match the personality of the reader. The result?  A 21% increase in response rate over the one-size-fits-all control

What We Did And Why It Works

We used third-party data to tag everyone on the file with their likely dominant personality trait, based on the Big Five model: Agreeableness, Conscientiousness, Openness, Extraversion, Neuroticism.

That 3rd party data (interests, lifestyle, shopping, demographics) is just messy raw ingredients.  But we have the recipe to turn it into psychological insight.

Once tagged, each person got the version of the letter written for their trait. No nth testing. No guesswork. No random spin of the creative wheel.

What Tailoring Looks Like

Each version told the same story — but in a way that made it easier for the reader to see themselves in it.

🟩 Agreeable

“Her world grew darker… Gathering her neighbors, she shared her story. ‘Let’s do this together.’”
Empathy, community, shared effort.

🟦 Conscientious

“She refused to give up… Clinics were far, but she found a solution.”
Determined, practical, goal-oriented.

🟨 Open

“The first thing she saw was light… Then, color—rich and electric.”
Imaginative, vivid, emotionally rich.

🟥 Extraverted

“The world burst into life… She rallied her neighbors.”
Social energy, connection, collective momentum.

🟧 Neurotic

“She gripped the walls of her home… The fear of total darkness loomed.”
Real vulnerability, fear, and resolution.

The control? Well-written. Clean. “On brand.” But it wasn’t written for anyone.  It was written to satisfy the subjective tastes of the person writing it and the 12-person committee reviewing it.

What Makes This Different — and Better

• One-size-fits-all isn’t tailored to the donor.
  It’s tailored to you — your preferences, your approval process, your branding guidelines. That’s not strategy. That’s internal comfort disguised as donor-centricity.

• Random nth testing stacks failure in your corner.
  If you’re randomly assigning people to versions, then every group contains all five personality types.  If your control has a innate trait match (questionable at best) then you’re still, on average, only speaking to 1 in 5. The other 80%? They’re mismatched by design. You’re testing noise against noise.

• Tailoring doesn’t cost more — unless you make it cost more.
  If you’re applying the same long review cycle to all five versions, you’re missing the point. You don’t need to be a behavioral scientist. We are.
  Review the shared base version. If it’s factually accurate and aligned to your mission, you’re done. The psychology takes it from there.

Why This Matters

When you tailor messaging to the mind of the reader, you reduce friction.
You make giving easier.
You make feeling seen easier.

This isn’t just about lifting response — though it does that. It’s about making your donors feel like the message was written for them — because it was.

This isn’t personalization as gimmick, it’s personalization as psychological alignment.  And it’s highly scalable.

Kevin