Table 1. Explanation of prioritisation criteria and levels in the DCE.

Criteria	Explanation	Level	Level definition
Prevalence of the condition within the target group	The phenotypical prevalence (genotype prevalence a penetrance) may differ between different conditions and within different target groups. Society may favour genetic tests for common conditions as they are more likely to detect an affected person.	Less than 0.05%	In line with the definition of the European Commission of Public Healtha, we define a rare condition as affecting less than 0.05% of a target group.
		Higher than/equal to 0.05% but less than 25%	We define a medium frequent condition as affecting less than 25% but more than or equal to 0.05% of a target group.
		Higher than/equal to 25%	Other
Severity of condition	The severity of the conditions tested for may be unequal. There might be justification in giving priority to severely ill patients as they are in greater need of health care.	Highly severeModerately severe	As Huntington disease is a frequently cited very severe genetic condition, we define ‘highly severe' as a patient suffering from Huntington disease or a condition of comparable severity.Other
Urgency of care	In the considered setting, the tests' aim may be to define a diagnosis or to predict the future risk of developing a disease. There might be a preference for conducting diagnostic testing as people with established symptoms face greater urgency for health resources.	DiagnosticPredictive	‘Diagnostic' testing is defined as any genetic test that aims to establish a diagnosis in a symptomatic person.Other
Clinical utility	Although some tests may have clinical utility, which could lead to a reduction in mortality/mobility (eg due to the availability of treatment or preventive options), other tests may be mainly for personal knowledge. Society may wish tests leading to mortality/morbidity reduction to have higher priority than those carried out just for personal knowledge.	Mortality/morbidity reductionPersonal knowledge	‘Mortality/morbidity reduction' is the case if the patient gains health benefit through available treatment or preventive options.Other
Alternatives available	There might be alternative means of diagnosing or predicting genetic conditions (eg clinical, biochemical). Society may have a preference for those tests where no alternative exists for diagnosis/prediction.	Not availableAvailable	Alternatives are ‘not available' if there are no alternative options for establishing a diagnosis/predicting the risk of contracting a disease.Other
Infrastructure for deliverability of testing and subsequent care	There might be a difference between competing tests in terms of availability of the infrastructure for the delivery of the test and routes for follow-up medical care (eg psychological care, medical treatment, inpatient health care). Society may have a preference for conducting those tests primarily where the infrastructure is fully established	EstablishedNot established	We define the infrastructure to be fully ‘established' if the test is routinely offered within genetic clinics.Other

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