NOS | ROB-NRSE | Degree of overlap | ||
---|---|---|---|---|
Comparability | C:Comparability of cohorts on the basis of the design or analysis | Bias due to confounding | 1.1: Is there potential for confounding of the effect of exposure in this study? | Unique |
1a: Study controls for the most important factor | 1.2: Was the analysis based on splitting follow up time according to exposure received? | Unique | ||
1b: Study controls for additional factor | 1.3. Were exposure discontinuations or switches likely to be related to factors that are prognostic for the outcome? | Unique | ||
Baseline confounding only | 1.4:Did the authors use an appropriate analysis method that controlled for all the important confounding domains? | Complete overlap | ||
1.5: Were confounding areas that were adjusted for measured validly and reliably by the variables available in this study? | Unique | |||
1.6. Did the authors avoid adjusting for post-exposure variables? | Unique | |||
Time-varying confounding only | 1.7: Did the authors use an appropriate analysis method that adjusted for all the critically important confounding areas and for time-varying confounding? | Unique | ||
1.8: Were confounding areas that were adjusted for measured validly and reliably by the variables available in this study? | Unique | |||
Selection | S1: Representativeness of exposed cohort | Bias in selection of participants into the study | 2.1: Was selection of participants into the study (or into the analysis) based on variables measured after the start of the exposure? | Unique |
1a: Truly representative | 2.2: Were the post-exposure variables that influenced selection associated with exposure? | Unique | ||
1b: Somewhat representative | 2.3: Were the post-exposure variables that influenced eligibility selection influenced by the outcome or a cause of the outcome? | Unique | ||
1c: Selected group of users | 2.4: Do start of follow-up and start of intervention coincide for most participants? | Unique | ||
1d: No description of the derivation of the cohort | 2.5: Were adjustment techniques used that are likely to correct for the presence of selection biases? | Unique | ||
S2: Selection of non-exposed cohort | ||||
2a: Drawn from the same community as the exposed cohort | ||||
2b: Drawn from a different source | ||||
2c: No description of the derivation of the non-exposed cohort | ||||
Selection | S3: Ascertainment of exposure | Bias in classification of Exposures | 3.1: Is exposure status well defined? | Unique |
3a: Secure record | 3.2: Did entry into the study begin with start of the exposure? | Unique | ||
3b: Structured interview | 3.3:Was information used to define exposure status recorded prior to outcome assessment? | Partial overlap | ||
3c: Written self-report | 3.4:Could classification of exposure status have been affected by knowledge of the outcome or risk of the outcome? | Partial overlap | ||
3d: No description | 3.5: Were exposure assessment methods robust (including methods used to input data)? | |||
S4: Demonstration of outcome of interest was not present at start of the study | ||||
4a: Yes | ||||
4b: No | ||||
Bias due to departures from intended exposures | 4.1: Is there concern that changes in exposure status occurred among participants? | Unique | ||
4.2: Did many participants switch to other exposures? | Unique | |||
4.3: Were the critical co-exposures balanced across exposure groups? | Unique | |||
4.4: Were adjustment techniques used that are likely to correct for these issues? | Unique | |||
Outcomes | O1: Was follow-up long enough for outcomes to occur (Yes/No) | Bias due to missing data | 5.1:Were there missing outcome data? | Partial overlap |
O3: Adequacy of follow-up of cohorts | 5.2: Were participants excluded due to missing data on exposure status? | Unique | ||
3a: Complete follow-up—all subjects accounted for | 5.3: Were participants excluded due to missing data on other variables needed for the analysis? | Unique | ||
3b: Subjects lost to follow up unlikely to introduce bias -small number lost | 5.4:Are the proportion of participants and reasons for missing data similar across exposures? | Partial overlap | ||
3c: Follow up rate large (%) and no description of those lost | 5.5: Were appropriate statistical methods used to account for missing data? | Unique | ||
3d: No statement | ||||
Outcomes | O2: Assessment of outcome | Bias in measurement of outcomes | 6.1:Could the outcome measure have been influenced by knowledge of the exposure received? | Partial overlap |
2a: Independent blind assessment | 6.2: Was the outcome measure sensitive? | Unique | ||
2b: Record linkage | 6.3:Were outcome assessors unaware of the exposure received by study participants? | Partial overlap | ||
2c: Self report | 6.4:Were the methods of outcome assessment comparable across exposure groups? | Partial overlap | ||
2d: No description | 6.5: Were any systematic errors in measurement of the outcome unrelated to exposure received? | |||
Bias in selection of the reported result | 7.1: Is the reported effect estimate likely to be selected, on the basis of the results, from multiple outcome measurements within the outcome domain? | Unique | ||
7.2: Is the reported effect estimate likely to be selected, on the basis of the results, from multiple analyses of the exposure-outcome relationship? | Unique | |||
7.3: Is the reported effect estimate likely to be selected, on the basis of the results, from different subgroups? | Unique |