Information checked: 21 July 2026.
Testimonials and case studies can reduce uncertainty only when they are genuine, relevant and presented without hiding material context. In the UK, fake reviews and concealed incentivised reviews are banned practices, and advertising claims still require evidence.
In brief: Keep consent, provenance and substantiation for every trust claim.
Use different evidence for different jobs
Evidence formats
- Short testimonial
- Best use: Customer experience or service quality; Required record: Original wording, permission and contact record
- Review-platform extract
- Best use: Independent customer feedback; Required record: Source URL, date and accurate quotation
- Case study
- Best use: Process, constraints and measured outcome; Required record: Client approval, methodology and evidence
- Logo
- Best use: Recognisable relationship; Required record: Permission and scope of relationship
- Aggregate rating
- Best use: High-volume review summary; Required record: Current source, calculation and moderation policy
Publish reviews responsibly
- Do not write reviews for customers or suppress genuine negative feedback.
- Disclose incentives clearly and do not make them conditional on positivity.
- Maintain a published policy where the site collects or republishes consumer reviews.
- Moderate for authenticity and prohibited content using proportionate controls.
- Keep factual claims in testimonials subject to the same evidence standard as other advertising.
Write case studies with limits
Explain the starting point, work performed, time period, measurement method and factors outside the supplier’s control. Do not imply that one result is typical for every customer.
Before you publish
The business should be able to produce consent, source and evidence for each published item and remove it promptly if permission or accuracy changes.
Where businesses get caught out
Businesses sometimes edit customer wording until it becomes a stronger claim, publish an incentivised review without disclosure or retain a case study after permission has changed. Another risk is quoting a percentage improvement without preserving the baseline and measurement method.
Evidence and records to preserve
- Original testimonial and contact record
- Publication permission and expiry conditions
- Incentive disclosure
- Case-study measurement evidence
- Removal and correction procedure
Start with this
Select three published testimonials or case studies and reconstruct their evidence file. If the business cannot prove wording, permission and factual claims, correct or remove them.
Sources and date checked
This practical guidance was checked against the following primary sources. It is general information, not legal advice; obligations depend on the business, customer, product and jurisdiction. Date checked: 21 July 2026.
Keep the decision under your control
Retain the relevant accounts, source material, supplier terms and recovery information. Recheck changing prices, interfaces and rules before acting.