title: Potential for technical errors and subverted allocation can be reduced if certain guidelines are followed: examples from a web-based survey.
abstract: OBJECTIVE
  To elicit researchers' experiences and knowledge of how the randomization process can be undermined.
  
  
  METHODS
  Web-based survey conducted in February 2006 using a convenience sample of individuals who are, or have been, involved in some aspect of randomized controlled trials.
  
  
  RESULTS
  Thirty responses were received that described incidences of manipulation. Seven reasons were identified for manipulation: interest of participants, demonstrating treatment efficacy, treatment preference, lack of knowledge, pressure from participants, pressure from trial workers, and practical or technical concerns. In many cases when manipulation was discovered, it was rarely mentioned in the trial publication. Twenty-three responses that described technical errors were received. Technical errors were reported for both the generation and implementation stages of the randomization process.
  
  
  CONCLUSIONS
  This study provides further evidence on trial subversion and highlighted that the potential for technical errors can be reduced, and in most cases eliminated, if certain guidelines are followed. Recommendations are as follows: use simple randomization where possible, use third party allocation, test computer randomization programs prior to participant recruitment and ensure that individuals are aware of the procedures needed to be performed if the treatment allocations cannot be accessed using the intended methods.
authors.affiliation: York Trials Unit, Department of Health Sciences, University of York, York, United Kingdom. ceh121@york.ac.uk
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Hewitt
authors.forename: David J
authors.initials: DJ
authors.lastname: Torgerson
authors.forename: Vance W
authors.initials: VW
authors.lastname: Berger
mesh_terms: D015982:Bias; D006801:Humans; D020407:Internet; D010358:Patient Participation; D017410:Practice Guidelines as Topic; D016032:Randomized Controlled Trials as Topic / Q000592:standards*; D011795:Surveys and Questionnaires; D014342:Truth Disclosure / Q000941:ethics