Revision as of 13:40, 23 September 2010 editEmble64 (talk | contribs)269 edits Adding funding bias (came from modification of the main bias page)← Previous edit | Revision as of 01:44, 18 November 2010 edit undo130.243.96.180 (talk)No edit summaryNext edit → | ||
Line 1: | Line 1: | ||
In ], the term '''bias''' refers to several different concepts: | In ], the term '''bias''' refers to several different concepts: | ||
*], where individuals or groups are more likely to take part in a ] project than others, resulting in ]s. This can also be termed ''Berksonian bias''<ref>Rothman, K.J. ''et al.'' (2008) Modern epidemiology. ''Lippincott Williams & Wilkins'' pp.134-137.</ref>. | *], where individuals or groups are more likely to take part in a ] project than others, resulting in ]s. This can also be termed ''Berksonian bias''<ref>Rothman, K.J. ''et al.'' (2008) Modern epidemiology. ''Lippincott Williams & Wilkins'' pp.134-137.</ref>. | ||
**] arises from evaluating diagnostic tests on biased patient samples, leading to an overestimate of the sensitivity and specificity of the test. | **] arises from evaluating diagnostic tests on biased patient samples, leading to an overestimate of the ] and ] of the test. | ||
* The ] is the difference between an estimator's expectation and the true value of the parameter being estimated. | * The ] is the difference between an estimator's expectation and the true value of the parameter being estimated. | ||
** ] is the bias that appears in estimates of parameters in a regression analysis when the assumed specification is incorrect, in that it omits an independent variable that should be in the model. | ** ] is the bias that appears in estimates of parameters in a regression analysis when the assumed specification is incorrect, in that it omits an independent variable that should be in the model. |
Revision as of 01:44, 18 November 2010
In statistics, the term bias refers to several different concepts:
- Selection bias, where individuals or groups are more likely to take part in a research project than others, resulting in biased samples. This can also be termed Berksonian bias.
- Spectrum bias arises from evaluating diagnostic tests on biased patient samples, leading to an overestimate of the sensitivity and specificity of the test.
- The bias of an estimator is the difference between an estimator's expectation and the true value of the parameter being estimated.
- Omitted-variable bias is the bias that appears in estimates of parameters in a regression analysis when the assumed specification is incorrect, in that it omits an independent variable that should be in the model.
- In statistical hypothesis testing, a test is said to be unbiased when the probability of rejecting the null hypothesis exceeds the significance level when the alternative is true and is less than or equal to the significance level when the null hypothesis is true.
- Systematic bias or systemic bias are external influences that may affect the accuracy of statistical measurements.
- Detection bias is where a phenomenon is more likely to be observed and/or reported for a particular set of study subjects. For instance, the syndemic involving obesity and diabetes may mean doctors are more likely to look for diabetes in obese patients than in less overweight patients, leading to an inflation in diabetes among obese patients because of skewed detection efforts.
- Funding bias may lead to selection of outcomes, test samples, or test procedures that favor a study's financial sponsor.
- Reporting bias involves a skew in the availability of data, such that observations of a certain kind may be more likely to be reported and consequently used in research.
- Data-snooping bias comes from the misuse of data mining techniques.
If an internal link led you here, you may wish to change the link to point directly to the intended article.
References
- Rothman, K.J. et al. (2008) Modern epidemiology. Lippincott Williams & Wilkins pp.134-137.