Phase 3: Delphi Panel

The defined actions from the expert meeting were prioritized through an online Delphi process. The Delphi technique has been a widely accepted method for data collection and reaching consensus among respondents within their domain of expertise (Dalkey and Helmer, 1963; Hsu and Sandford, 2007; Burke et al., 2009).

We aimed to obtain consensus of a heterogeneous Delphi panel on the prioritization of actions for implementation of PGx in primary care (see Figure 3 ). Twenty-seven experts were purposively selected and invited with similar expertise fields as the expert meeting.

Steps of the Delphi procedure including cutoff values.

Twenty experts accepted the invitation and 18 experts completed all rounds (response rate: 74.1%). Each expert e-mailed their prioritizations with arguments in three separate rounds between April and July 2017. Between rounds, all participants received an anonymized overview of answers and arguments in the next questionnaire.

The initial Delphi questionnaire contained 16 actions and suggestions for designated stakeholder(s). Participants were asked to score each action on importance on a five-point Likert scale, give a rationale for their score, and could suggest additional or different designated stakeholder(s). The questionnaire was finalized with a question to prioritize a top 3 of the actions for implementation of PGx in primary care. Criteria for consensus for each round were applied as described by Houwink et al. (Houwink et al., 2012) and Kendall’s W was calculated as a coefficient for concordance in the final prioritization by participants. A p value of ≤0.05 was considered statistically significant.

To analyze if certain experts within a group showed higher correlation in ranking the actions, participants were stratified. Each participant was allocated based on self-reported expertise. The groups were: scientists, pharmacists, policy experts, patient representatives, and GPs.