By the numbers. Largest patient-satisfaction measurement firms. Ranked by total number of engagements in 2011.
D003253:Consultants / Q000706:statistics & numerical data; D006302:Health Services Research / Q000458:organization & administration* / Q000706:statistics & numerical data; D006801:Humans; D017060:Patient Satisfaction / Q000706:statistics & numerical data*; D014481:United States