Table 2

Methodological decisions to improve study quality

Criteria42 Methodological decisions to improve quality
Study design
 Inception cohort

  • Clear description of population

  • Clear description of the participants at baseline

 Source population

  • Clear description of population

  • Clear description of sampling frame and recruitment (method and timing)

 Inclusion and exclusion criteria

  • Clarity of eligibility criteria

 Prospective design

  • Clarity of study design

Study attrition
 Number of drop-outs

  • Adequate participation rate

  • Clear description of attempts to collect information on participants who dropped out

  • Reporting numbers and reasons for loss to follow-up

 Information provided on method of management of missing data

  • Appropriate methods of imputation of missing data

Predictive factors
 All predictive factors described used to develop the model

  • Clear definition of predictive factors

  • An adequate proportion of participants has complete data for the predictive factor

 Standardised or valid measurements

  • The measurement of the predictive factor is reliable and valid

  • The measurement of the predictive factor is the same for all participants

 Linearity assumption studied

  • Linearity of data will be reported

 No dichotomisation of predictive variables

  • Continuous variables will be reported where possible

 Data presentation all predictive factors

  • Complete data will be presented

Outcome measures
 Description of outcome measures

  • The outcome is clearly defined

 Standardised or valid measurements

  • The measurement of the outcome is reliable and valid

  • The measurement of the outcome is the same for all participants

 Data presentation of most important outcome measures

  • Complete data will be presented

Analysis
 Presentation of univariate crude estimates

  • An appropriate strategy for model building is described

  • An adequate statistical model described

 Sufficient numbers of subjects per variable

  • Adequate data will be presented

 Selection method of variables explained

  • Sufficient data will be presented to enable assessment of the adequacy of the analytic strategy

  • All results will be reported

 Presentation of multivariate estimates

  • An appropriate strategy for model building is described

  • An adequate statistical model described

Clinical performance/validity
 Clinical performance

  • Clinical performance of the model will be reported

 Internal validation

  • Internal validation will be reported

 External validationNot a focus of this study