Testimonials and Case Studies: What’s Wrong?

Case Study – In-depth analysis of particular individual

e.g., HM’s severe retrograde and anterograde amnesia following lobectomy

  • Case of HM allowed researchers to study short- and long-term memory consolidation
    • Led to lots of controlled experiments
  • Similarly Piaget’s case study used to develop own theory, allowed investigation with series of controlled experiments

∴ Case studies cannot be used as evidence of theories, used for generating ideas

Case studies, testimonials, anecdotes can never be used as scientific evidence and cannot support theories

  • Helpful for developing theories; never used for evidence of theories

Testimonials – Persuasive claim by individual, a statement of endorsement

  • Source of inspiration for research, but not scientific evidence

What’s Wrong with Testimonials and Case Studies?

  • They lack proper controls that experiments contain
  • Could not rule out other alternative explanations
    • Controls can rule out alternative explanations
      e.g., Amazing Randi went on talk show and reported UFO sightings when no such thing occurred – witness after witness called in
  • Testimonials are easy to find
  • Generic descriptions that describe everyone are sometimes used (e.g., Personality reading)
  • Scientology Churches have personality test: what’s wrong, what needs to be fixed, etc.
  • Testimonials can be found regardless of therapeutic value
  • Mere act of suggestion will lead people to see changes

Placebo Effect – Changes occur without therapeutic efficacy due to expectation of change

Spontaneous Remission – Many conditions go away without any treatment (e.g., cases of depression, arthritis, MS, cancer, etc.)

  • Can’t just give treatment and evaluate improvement because 30% improve due to placebo effect and spontaneous remission
  • Must use control group with placebo, with neither group knowing which condition it is in – both placebo effect and spontaneous remission controlled for, differences due to active ingredient of drug
    e.g. Alcohol on judgement… placebo effect is strong!
  • Expectation of therapeutic efficacy has massive effect on treatment

The Vividness Effect

  • Why are we all so easily influenced by testimonials?
  • Availability heuristic – We try to recall based on how easily we can recall examples
    e.g., Listen to list of names of men and women, famous names – listeners claim they heard more – stood out in memory
  • Vividness effect – information that are attention-grabbing, emotionally interesting, and image provoking weighted more heavily
    e.g., Plane crash versus car crash, even though driving is a lot more dangerous
  • Most people have no idea of statistical probability and statistics, but even with information, people are still more likely to be grabbed by testimonials and media
    • Much more influenced by person than by statistics, even with access to both sides of the story

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