Different teams have used different questionnaires to evaluate PKB's usability. Find below some examples:
Eg https://pkb.wufoo.com/forms/abmu-patient-portal-survey/
Eg https://pkb.wufoo.com/forms/sandwell-patient-survey/
Eg https://pkb.wufoo.com/forms/patients-know-best-metrics-for-hiv-janssen/