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Table 3 Items chosen to assess risk of bias of the included studies

From: What is the prevalence of musculoskeletal problems in the elderly population in developed countries? A systematic critical literature review

Item number from original study* Dimension of bias Methods domain Assessment question Criteria / definitions / categories
Q2 Selection bias Sample definition and selection · Are critical inclusion/exclusion criteria clearly stated? · Target population described?
· Ascertainment procedure for target sample described?
· Study sample representative of the target population described?
· Age range, gender, etc. described?
· Specific inclusion/exclusion criteria stated?
· Sample size described?
Q3 Information bias Sample definition and selection · Are the inclusion/exclusion criteria measured using valid and reliable measures · Ascertainment procedure: Random, stratified, cluster, etc. (if applicable)
· Registry (census, GP databases) (reporting bias?) (if applicable)
· Medical records (clinical or hospital records) (if applicable)
· Non-response analysis (non-response bias) (if applicable)
· Sample size: is it justified or is a power calculation provided?
Q14 Information bias Soundness of information · Are outcome measures assessed using valid and reliable measures? · Questionnaire (is it valid and/or reproducible?) (if applicable)
· Registry (i.e. census, GP databases) (reporting bias?) (if applicable)
· Interviewing bias (i.e. structured, semi-structured, objective) (if applicable)
· Self-reporting (risk of recall bias; shorter recall better than longer recall) (if applicable)
· Observation, examination procedure (observer bias?) (if applicable)
· Q7 · Performance bias · Exposure · What is the level of detail in describing the outcome? · Definition of the MSK condition; anatomical, physiological. (required)
· Definition of symptom(s) (pain, problem, other) (required)
· Definition of period of symptom(s) (required, only if applicable)
· Description of pain intensity (if applicable, not required)
· Overall judgment · Low risk of bias: Bias, if present, is unlikely to alter the results seriously
· Unclear risk of bias: Impossible to determine risk of bias (either missing or not described well enough)
     · High risk of bias: Bias may alter the results seriously
  1. * Viswanathan M, Berkman ND. Development of the RTI item bank on risk of bias and precision of observational studies. J Clin Epidemiol 2011, 65:163-178.