Show Summary Details
Page of

Error and bias in observations 

Error and bias in observations
Chapter:
Error and bias in observations
Author(s):

Mark Elwood

DOI:
10.1093/med/9780199682898.003.0006
Page of

PRINTED FROM OXFORD MEDICINE ONLINE (www.oxfordmedicine.com). © Oxford University Press, 2016. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in Oxford Medicine Online for personal use (for details see Privacy Policy and Legal Notice).

date: 17 September 2019

This chapter distinguishes error and bias, non-differential and differential misclassification distinguished. Non-differential misclassification almost always biases results toward the null, while differential misclassification can affect results in any direction. Methods to minimise observation bias include single, double and triple blind assessment. It discusses recall and other biases, with methods of assessment and avoidance, and practical issues on reducing error and bias. In part two, it shows how to measure and adjust for observational error and bias, including Kappa and adjusting for non-differential misclassification, and similar adjustments using continuous exposure measures. Effects with more than two categories of outcome or exposure, and of the misclassification of confounders are discussed. In assessing the accuracy of information, sensitivity, specificity, and predictive value are defined, and the calculation of the effects of misclassification using sensitivity and specificity are shown.

Access to the complete content on Oxford Medicine Online requires a subscription or purchase. Public users are able to search the site and view the abstracts for each book and chapter without a subscription.

Please subscribe or login to access full text content.

If you have purchased a print title that contains an access token, please see the token for information about how to register your code.

For questions on access or troubleshooting, please check our FAQs, and if you can't find the answer there, please contact us.