Table 1.

The German Network Health Services Research (www.dnvf.de) criteria for assessment of registry quality. For details see [17]

Domain	Item
1. Systematics and Appropriateness	Registry protocol
	Aims and expected benefits
	Registry organization
	Patient rights and data safety
	Registry design
	Data acquisition and processing
	Data analyses, reporting and publication
	Steering Committee
2. Standardization	Definitions and standard operating procedures
	Training for data entry and verification
3. Validity of the sampling procedure	Definition of inclusion and exclusion criteria
	Completeness and representativity of data
	Consideration of sample size and effect
	Consideration of confounders and biases
4. Validity of data collection	Assessment of data: completeness, plausibility, distribution, Concordance
	Handling of missing data, follow-up and dropout
	Unique identifiers and risk of duplicate data entry
	Monitoring and audits
5. Validity of statistical analyses and reports	Patient/data flow scheme
	Handling of missing data
	Assessment of baseline data and outcome measures, Evaluation of balance in comparative analyses
	Assessment of precision measures
	Methods against bias and confounders
	Adjustment for multiple inference testing
	Assessment of relative and absolute effects, adjusted and Unadjusted results
	Multivariate modeling for complex questions
	Consideration of timeline in longitudinal data
	Control of cluster effects
	Validity of statistical analyses and reports
6. General demands for registry quality	Transparency towards limitations
	Acceptance among patients and institutions
	Transparency and scientific independence
	Flexibility and adaptability
	Topicality