Study design
Allocation concealment
Protecting the randomisation process so group assignment cannot be predicted or manipulated.
What it means
Definition
Allocation concealment. Allocation concealment prevents researchers or clinicians from knowingly or unknowingly steering certain participants into one group. It is distinct from blinding after assignment.
What it can tell you
It can show how close the evidence is to a real human health outcome.
What it cannot tell you
It cannot prove that a treatment works in people unless human outcome data are available.
Headline trap
Why this matters in headlines
A trial can be randomised but still biased if staff can foresee the next treatment allocation.