The Variability of Results

  • Christopher J. Bulpitt
Part of the Developments in Biostatistics and Epidemiology book series (DBEP, volume 1)


Even when the results of a trial are free of bias, the measurements on which they are based are still subject to random variability. Often the variability can be both estimated from its repeatability and reduced by quality control. The measurements may vary between subjects and this variability can be reduced by employing the within subject cross-over trial design. It must also be remembered that a measurement may be very repeatable but either not provide the correct result (low accuracy) or measure something other than that intended (low validity).


Heart Attack Blood Pressure Measurement Korotkoff Sound Mercury Column Random Blood Sugar 


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Copyright information

© Springer Science+Business Media Dordrecht 1983

Authors and Affiliations

  • Christopher J. Bulpitt
    • 1
    • 2
    • 3
  1. 1.Department of Medical Statistics and EpidemiologyLondon School of Hygiene and Tropical MedicineLondonUK
  2. 2.Royal Postgraduate Medical SchoolLondonUK
  3. 3.Hammersmith HospitalLondonUK

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