Standard Article

Allocation Concealment

  1. Kenneth F. Schulz

Published Online: 14 DEC 2007

DOI: 10.1002/9780471462422.eoct061

Wiley Encyclopedia of Clinical Trials

Wiley Encyclopedia of Clinical Trials

How to Cite

Schulz, K. F. 2007. Allocation Concealment. Wiley Encyclopedia of Clinical Trials. .

Author Information

  1. Family Health International, Research Triangle Park, North Carolina

Publication History

  1. Published Online: 14 DEC 2007


Allocation concealment, as an integral part of randomization, implements an allocation sequence. Inadequate allocation concealment can lead to exaggerated estimates of treatment effect, but with scope for bias in both directions. Without adequate allocation concealment, even proper random assignment sequences can be subverted. Investigators must recognize the inquisitiveness and ingeniousness of human nature and “immunize” trials against selection and confounding biases with proper allocation concealment.


  • allocation concealment;
  • randomization;
  • bias;
  • trials;
  • sequence;
  • treatment;
  • blinding