Clinical trials of vaccines and drugs]

• clinical trials of vaccines and drugs:

  • test safety and effectiveness
  • group size= large to reduce magnitude of experimental error
• randomised= groups formed in a randomised way to reduce bias in distribution of age / gender
• double-blind= neither subjects nor researches know which group receives drug/vaccine or placebo, this prevents biased interpretation of results
• placebo= one group gets drug/vaccine, other gets placebo (eg sugar pills), this allows valid comparisons