Table 5.

Assessment of quality score of studies performing a risk prediction analysis in patients submitted to liver resection

	Quality score Median (range)	Maximum score
Study participation	6 (2–9)	10
Population described for key characteristics	1	2
Sampling and recruitment described	2	2
Inclusion/exclusion criteria described	1	2
Adequate participation	2	2
Baseline study sample described	1	2
Prognostic factor measurement	9 (4–10)	12
Prognostic factors are clearly described or defined	2	2
Continuous variables reported, or appropriate cut-off points used	1	2
Prognostic factors are valid and reliable	2	2
Study sample has complete data for prognostic factors	2	2
Same method and setting of measurement for all study participants	2	2
Appropriate methods used for missing prognostic data	0	2
Outcome measurement	4 (0–6)	6
Definition of the outcome described	2	2
Outcome measure and method are valid and reliable	1	2
Same method and setting of measurement for all study participants	1	2
Confounding factor measurement	8 (4–10)	14
Important confounders are measured	1	2
Clear definitions of confounders described	2	2
Measurement of all confounders is valid and reliable	1	2
Same method and setting of measurement for all study participants	2	2
Appropriate methods used for missing confounder data	0	2
Important confounders accounted for in the study design	1	2
Important confounders accounted for in the analysis	1	2
Analysis	7 (4–8)	8
Sufficient presentation of data to assess the adequacy of the analysis	1	2
Strategy for model building appropriate and based on a conceptual model	2	2
Adequate selection of model for the design of the study	2	2
No selective reporting of results	2	2
Median quality score of studies	34 (24–41)	50