Table 3.

Intervention fidelity strategies

Category [22]	Goals [22]	Elements of the ISDM study
Design of study	• Ensure same treatment dose within conditions.	• Curriculum and media are standardised for both study arms
	• Ensure equivalent dose across conditions.	• Intervention and control-intervention are similar in framing, duration and structure
	• Plan for implementation setbacks	• For both intervention and control-intervention, two diabetes educators are trained to ensure the completion of the counselling sessions
Training providers	• Standardize training	• All diabetes educators are trained in standardised train-the-trainer sessions
	• Ensure provider skill acquisition
	• Minimize “drift” in provider skills	• Educational material is standardised
		• Optimal patient counselling is demonstrated
	• Accommodate provider differences (adequate level of training, skills, experience and professional background)	• Providers practise counselling under supervision of a research fellow and subsequent feedback
		• Providers assess the patient knowledge questionnaire to ensure skill acquisition
Delivery of intervention	• Control for provider differences	• Counselling sessions are video-taped, constantly analysed, and fed back by a research fellow
	• Reduce differences within treatment	• Counselling protocol: deviation from curriculum (duration, material use, content, didactics) is documented
	• Ensure adherence to protocol
	• Minimize contamination between conditions
Receipt of intervention	• Ensure participant knowledge	• Questionnaire cards at the end of the counselling session. If there are difficulties in understanding, the diabetes educator discusses and corrects the answer and repeats the information
	• Ensure participant ability to use cognitive skills
	• Ensure participant ability to perform behavioural skills
Enactment of treatment skills	• Ensure participant use of cognitive skills	• Patients set individual treatment goals for heart attack prevention
	• Ensure participant use of behavioural skills	• If patients make treatment decisions that differ from their current treatment goals a physician is consulted for clarification