Who uses the patient internet portal? The PatientSite experience. Journal of the American Medical Association 13 (1),91-95. Hibbard, J. H., Stockard, J., Mahoney, E.R. & Tusler, M. (2004). Development of the Patient Activation Measure (PAM): conceptualizing and measuring activation in patients and consumers. Health Services Research 39,1005-1026..