Table 2

Overview of identified key issues and how they triangulate across the literature review and the three studies

Key finding	Literature review	Interviews	Focus groups	Delphi survey
Limited knowledge of available databases.	Agreement	Agreement	Agreement	Agreement
Understanding of pharmacovigilance based on WHO definition.	Not addressed	Partial agreement	Partial agreement	Not addressed
Limitations of current pharmacovigilance systems.	Not addressed	Agreement	Agreement	Not addressed
Data linkage is useful for pharmacovigilance research.	Agreement	Agreement	Partial agreement	Partial agreement
Adherence to legislation is necessary.	Agreement	Agreement	Agreement	Not addressed
It is not clear which legislation is relevant.	Partial agreement	Agreement	Agreement	Not addressed
Data quality is important for data linkage.	Agreement	Agreement	Agreement	Partial agreement
The responsibility for the linked data lies with the data owner.	Silence	Agreement	Partial agreement	Silence
Data ownership needs to be clarified.	Partial agreement	Agreement	Silence	Agreement
The NHS should be a facilitator of the data linkage.	Silence	Partial agreement	Agreement	Disagreement
The benefits of the data linkage outweigh the risks.	Partial agreement	Agreement	Partial agreement	Disagreement*
Professional guidelines might prevent data sharing.	Silence	Agreement	Partial agreement	Disagreement
Conditional support if data linkage available.	Agreement	Agreement	Agreement	Agreement
Information governance is a facilitator of data linkage.	Agreement	Agreement	Agreement	Agreement
Feedback from studies using the linked data is a facilitator.	Agreement	Silence	Agreement	Agreement
Anonymisation is mandatory.	Partial agreement	Partial agreement	Agreement	Agreement
Information of and input from the public is important.	Agreement	Agreement	Agreement	Agreement
An opt-out option for patients is acceptable.	Agreement	Partial agreement	Partial agreement	Agreement
Technical problems can be solved.	Agreement	Agreement	Agreement	Agreement
Use of CHI number is acceptable.	Silence	Agreement	Agreement	Agreement
Safeguards like sanctions should be used.	Agreement	Agreement	Partial agreement	Silence
Ethical approval will be required.	Agreement	Agreement	Agreement	Agreement
Data linkage should not impact negatively on current workload.	Agreement	Agreement	Agreement	Agreement
A certain amount of patient identifiable data will be necessary for the linkage.	Agreement	Agreement	Agreement	Silence
Assurance of confidentiality would facilitate support.	Agreement	Partial agreement	Partial agreement	Agreement

Bold font indicates agreement across three or more arms.
Agreement: key finding has been identified; partial agreement: finding is partially covered; disagreement: contradictory statement; silence: not apparent; not addressed: subject not addressed in study.
*Disagreement only in the way that this was mentioned but dropped across the rounds, indicating that there was no consensus on this item, hence disagreement rather than silence.
CHI, Community Health Index.