attrition bias


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attrition bias

A systematic error caused by the selective occurrence and biased handling of protocol deviations and losses to followup, which may lead to results that differ from a study’s true values.
 
Preventive measures
Trialists should ensure low dropout rates, high compliance rates and minimise missing outcomes data.
References in periodicals archive ?
This is where ITT should appear--it is a measure of attrition bias (incomplete outcome data).
2011) study, two non-responders (defined by an inability to show any adaptive response during the training slips) in the intervention group were excluded from their analysis, thus increasing the risk of attrition bias.
Assessment of attrition bias considers whether there may be systematic differences between groups in withdrawals from a study The four studies included in the review were performed in well-defined, and well-controlled, environments --largely due to their experimental nature.
I would argue that to account for attrition bias, remission rates calculated using the cases available for follow-up should be adjusted using worst-case imputation," Dr.
Only chiropractic data with low risk of selection bias (random sequence generation and allocation concealment), low risk of performance blinding (parental blinding) and low risk of attrition bias (selective reporting) were included.
The studies reported the outcomes of all enrolled subjects, so the risk of attrition bias was low; but in the absence of study registration materials it was impossible to determine whether or not there was selective reporting (i.
This tool assesses risk of bias within the following domains: selection bias, performance bias, detection bias, attrition bias, reporting bias, and other bias.
Our estimates of the influence of single parenthood on children's socioeconomic outcomes are vulnerable to two potential sources of attrition bias.
Attrition bias can affect the findings of the subsequent rounds of a panel survey, so it is important to examine the extent of sample attrition and determine whether it is random or has affected the representativeness of the panel sample.
The model of attrition bias presented here, and the standard based on it, is an effort to protect consumers of research from drawing mistaken conclusions because of bias (in this case, attrition bias) in impact estimates.
1) Among these biases, the attrition bias is somewhat different in that it cannot be controlled solely by the effort of researchers.
However, the review notes, "it is unclear whether alcohol causes a hostile attrition bias or whether it is attributable to an aggressive response pattern learned early in life as all subjects had at least one alcoholic parent.