LandingBoost
LandingBoost research · Updated 2026-07-17

Social Proof Tests: Where Testimonials and Logos Actually Worked

Published tests of testimonials and customer logos show that proof placement and proximity to the decision can matter more than simply adding a logo row.

Short answer: Social proof is most useful when it answers doubt at the moment a visitor is deciding. WikiJob's same testimonials had no discernible impact lower on the page, then increased purchases when placed near the decision. Other published tests reported signup lifts from customer logos, but multi-change redesigns should not be treated as proof that testimonials caused the whole result.
WikiJob social proof experiment: testimonials moved near the purchase decision and reported 34% more purchases
Reported results from third-party case studies. They are not forecasts for your page. We preserve the measured metric and call out missing or confounded context.

The practical pattern

  • Place proof beside the claim or decision it supports, not in a decorative strip far away.
  • Use concrete customer language, identity, or outcome; generic praise carries less information.
  • Separate isolated proof tests from redesigns that changed copy, layout, and proof together.

Published experiments

What changed, what the source measured, and what the result does—or does not—prove.

WikiJob

Purchases

Evidence B
BeforeThe same testimonials were displayed farther down the page and had no discernible conversion impact.
ChangePlaced three lines of customer testimonials near the aptitude-test purchase decision.
MeasuredPurchases
Reported result: +34% purchases.

How to interpret it: The public case makes placement the important contrast. It does not publish sample size or statistical confidence in the text available to us.

Read the primary case study at VWO →
Teamleader

Free-trial signup conversion

Evidence B
BeforeOriginal free-trial signup page without the tested customer-logo treatment.
ChangeAdded customer logos to one signup-page variation.
MeasuredFree-trial signup conversion
Reported result: Conversion rate increased from 36% to 40.3%.

How to interpret it: That is a 4.3 percentage-point increase, or roughly 11.9% relative uplift. The published case does not expose every experimental detail needed to generalize the result.

Read the primary case study at VWO →
Envoy

Signups

Evidence B
BeforeCustomer brands were not prominent enough on the homepage.
ChangeIncreased the prominence of brands using Envoy to reduce signup anxiety and strengthen credibility.
MeasuredSignups
Reported result: +12% signups for the customer-logo variation.

How to interpret it: A separate use-case variation also won at +8%, showing that proof and product relevance can both reduce uncertainty. This is one company's result, not an expected lift for every page.

Read the primary case study at Conversion →

Questions founders ask

Where should testimonials go on a landing page?

Put the most relevant proof close to the claim, CTA, or purchase decision it supports. WikiJob's published case suggests the same proof can perform differently when its placement changes.

Are customer logos enough for social proof?

Logos can reduce perceived risk, but they rarely explain an outcome. Combine recognizable logos with a concrete customer result when you can substantiate it.

How do I test social proof?

Change one proof variable at a time—placement, specificity, customer identity, or format—and measure signups or purchases. Do not attribute a full-page redesign's uplift to testimonials alone.

Method and limits

  • This article uses public case studies from the LandingBoost CRO evidence registry.
  • Evidence grade B means the source names a testable change and a measured result, but not every detail required for independent replication is public.
  • Vendor-published success stories overrepresent winning tests. A result is a hypothesis input, not an expected uplift.

Related research

CTA tests
Three published landing page experiments show when CTA wording, navigation labels, and button choices increased signups or clicks—and where the result stopped short of revenue.
Form friction tests
Evidence from published form and journey experiments shows how progressive fields, shorter processes, and clearer paths affected lead and conversion rates.

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