ascertainment bias


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ascertainment bias

systematic failure to represent equally all classes of cases or people supposed to be represented in a sample.

as·cer·tain·ment bi·as

(as-ĕr-tān'mĕnt bī'ăs)
Systematic failure to represent equally all classes of cases or people supposed to be represented in a sample.
References in periodicals archive ?
This finding might be a limitation of our sample size or might indicate that the higher CFR for persons [greater than or equal to] 45 years of age from other studies resulted from ascertainment bias arising from inclusion of only hospitalized case-patients or those reported to the surveillance system, whereas ascertainment of cases in this report was community-based.
15] investigators believe that the increase reflected ascertainment bias.
At this time, it is not known if factors such as ascertainment bias, prevalence of statin use, inclusion of revascularization procedures as a CVD event, and follow-up time could account for differences in the CVD risk estimates between the different population studies.
The strengths of the study are its large size and varied location of participants from all across the USA and the adjustments for a range of socioeconomic indicators to minimise ascertainment bias.
Ascertainment bias, or decreased genetic variability in species that were not directly targeted in the original marker selection process, is a common finding in genetic studies of microsatellite loci among closely related species (Ellegren et al.
In single-child paternity cases, ascertainment bias was compensated for by counting every apparent null allele carrier parent as two null carriers.
Researchers, "found evidence of a strong association between COPD and lung cancer, but this was largely explained by the effect of smoking and is most apparent in recently diagnosed cases of COPD, suggesting a strong element of ascertainment bias.
On the risk side, there is the potential that reports of bladder cancer on dapagliflozin reflected an ascertainment bias.
Additionally, at least to some extent, higher reported prevalence of HCV infection among HIV-infected MSM compared with HIV-uninfected MSM might result from ascertainment bias rather than a true difference in disease prevalence.
Descriptions of many associated conditions and neuropsychological profiles in patients with TS attending specialised clinics are intriguing, but the observed association between TS and other conditions might be due to ascertainment bias, since those with more complex needs are more likely to be referred for professional evaluation and treatment.
I am among those researchers who have doubts about the veracity of the signals generated from administrative databases, which I believe suffer from major sources of uncontrolled bias, such as ascertainment bias.
Attempts to adjust for ascertainment bias has resulted in lower overall risks being estimated for BRCA1 and BRCA2 [20], especially when these studies include population-based series [21].