Sampling
The qualitative methods of the isPO OG evaluation contained the analysis of semi-structured interviews and focus groups with patients, isPO OGs, and professional isPO service providers. The acquisition of participants followed purposeful sampling (Patton Patients who were able to participate in an interview were acquired with the help of the care networks' psycho-oncologists. Then, the psycho-oncologists provided contact information for these selected patients to the isPO Trust Centre. The isPO Trust Centre ensured that the data exchange in the project was compliant with data protection regulations. It managed contact information of patients and service providers as well as pseudonyms for the different data sources to make data linkage possible. It was a unit within the institute responsible for the external evaluation of isPO but separated from the researchers both spatially and by personnel. For the interviews with isPO OGs, network coordinators and isPO case managers were asked to look for participants in their respective care network and provide their contact information. According to the isPO OG focus group, the HKSH-BV forwarded an invitation email from the evaluators to all certified isPO OGs so they could announce their participation to the isPO Trust Centre. The evaluators contacted the network coordinators and head psycho-oncologists directly. The network coordinators discussed within the team of the respective care network which members would participate in the focus groups with professional isPO service providers on care level and announced them to the evaluators. According to the purposeful sampling, it was requested that the participants cover professional service providers on all isPO care levels (isPO case managers, psychosocial professionals, and psychotherapists).