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Randomization: Beyond the closurization principle.

Lawrence H Moulton1

  • 1Departments of International Health and Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.

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|March 2, 2022
PubMed
Summary
This summary is machine-generated.

Restricting cluster randomized trials using baseline covariates ensures balance between study arms. This method, while improving balance, involves a trade-off with statistical validity, as explained by Fisher-Bailey principles.

Keywords:
Cluster randomized trialrandomizationstudy design

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Area of Science:

  • Biostatistics
  • Clinical Trials Methodology
  • Epidemiology

Background:

  • Cluster randomized trials (CRTs) often involve a limited number of clusters.
  • Baseline cluster-level covariates are frequently available before randomization.

Purpose of the Study:

  • To discuss the rationale and methods for restricting allocations in CRTs.
  • To explain the implications of restricted randomization on study validity.

Main Methods:

  • Review of restricted randomization techniques in cluster randomized trials.
  • Explanation of the Fisher-Bailey validity criterion.
  • Illustrative examples of the balance-validity trade-off.

Main Results:

  • Restricted randomization can effectively balance baseline covariates across study arms in CRTs.
  • The degree of restriction impacts the trade-off between achieving balance and maintaining statistical validity.

Conclusions:

  • Restricted randomization is a valuable tool for enhancing balance in CRTs with few clusters.
  • Careful consideration of the Fisher-Bailey validity is essential when implementing restricted randomization strategies.