Table 3.

Final multiple regression model with “overall research participant experience” as the outcome

Items included in model*	R2	Adjusted R2 for each additional question in the model**
• Treated with courtesy and respect by the investigator or research doctor	0.816	0.809
• Prepared for what happened by information and discussions provided before participation	0.896	0.888
• Research doctor or investigator listened carefully	0.939	0.932
• Prepared for what to expect by informed consent documents	0.950	0.942
• Knew how to reach research team	0.961	0.953
• Able to reach member of research team when needed	0.968	0.959

^*Item phrases summarize the content of the question and not its exact wording in the questionnaire.

^**Adjusted R² serves as an indicator of the ability of a subset of items in the questionnaire to explain overall research participant experiences (Adjusted R² – 0.959, F-4.44, p<0.046).