A study of adults older than 65 years investigated the effec…

A study of adults older than 65 years investigated the effect of the use of calming communication techniques by caregivers on the agitation level of patients experiencing stage 2 dementia. The researchers noted that the effectiveness of the calming communication techniques differed based on whether the caregiver was a family member or licensed medical personnel. In this study, which type of variable was the patient–caregiver relationship?