Levit K, Cowan C, Lazenby H.
et al. Health spending in 1998: signals of changes. Health Aff (Millwood).2000;19:124-132.
Dubois RW, Chawla AJ, Neslusan CA.
et al. Explaining drug trends: does perception match reality? Health Aff (Millwood).2000;19:231-239.
Prescription Drug Expenditures in 2000: The Upward Trend Continues. Washington, DC: National Institute for Health Care Management Foundation;
Berndt ER. The US pharmaceutical industry: why major growth in times of cost containment? Health Aff (Millwood).2001;20:100-114.
Penna P. Three-tier copay systems and consumer-centric care. J Managed Care Pharmacy.2000;6:351-354.
Leibowitz A, Manning WG, Newhouse JP. The demand for prescription drugs as a function of cost-sharing. Soc Sci Med.1985;21:1063-1069.
Reeder CE, Nelson AA. The differential impact of co-payment on drug use in a Medicaid population. Inquiry.1985;22:396-403.
Soumerai SB, Avorn J, Ross-Degnan D, Gortmaker S. Payment restrictions for prescription drugs under Medicaid: effects
on therapy, cost and equity. N Engl J Med.1987;317:550-556.
Soumerai SB, Ross-Degnan D, Avorn J.
et al. Effects of Medicaid drug-payment limits on admission to hospitals and
nursing homes. N Engl J Med.1991;325:1072-1077.
Soumerai SB, McLaughlin TJ, Ross-Degnan D.
et al. Effects of a limit on Medicaid drug-reimbursement benefits on the use
of psychotropic agents and acute mental health services by patients with schizophrenia. N Engl J Med.1994;331:650-655.
Harris BL, Stergachis A, Ried DL. The effect of drug co-payments on utilization and cost of pharmaceuticals
in a health maintenance organization. Med Care.1990;28:907-917.
Smith DG. The effects of co-payments and generic substitution on the use and
costs of prescription drugs. Inquiry.1993;30:189-198.
Walser BL, Ross-Degnan D, Soumerai SB. Do open formularies increase access to clinically useful drugs? Health Aff (Millwood).1996;15:95-109.
Johnson RE, Goodman MJ, Hornbrook MC, Eldredge MB. The impact of increasing patient prescription drug cost sharing on
therapeutic classes of drugs received and on the health status of elderly
HMO members. Health Serv Res.1997;32:103-122.
Johnson RE, Goodman MJ, Hornbrook MC, Eldredge MB. The effect of increased prescription drug cost-sharing on medical care
utilization and expenses on elderly health maintenance organization members. Med Care.1997;35:1119-1131.
Horn SD, Sharkey PD, Phillips-Harris C. Formulary limitations and the elderly: results from the Managed Care
Outcomes Project. Am J Manag Care.1998;4:1105-1113.
Stuart B, Zacker C. Who bears the burden of Medicaid drug co-payment policies? Health Aff (Millwood).1999;18:201-212.
Hillman AL, Pauly MV, Escarce JJ.
et al. Financial incentives and drug spending in managed care. Health Aff (Millwood).1999;18:188-200.
Motheral BR, Henderson R. The effect of a closed formulary on prescription drug use and costs. Inquiry.1999;36:481-491.
Tamblyn R, Laprise R, Hanley JA.
et al. Adverse events associated with prescription drug cost-sharing among
poor and elderly persons. JAMA.2001;285:421-429.
Motheral B, Fairman KA. Effect of a three-tier prescription copay on pharmaceutical and other
medical utilization. Med Care.2001;39:1293-1304.
Duan N, Manning WG, Morris CN, Newhouse JP. A comparison of alternative models for the demand for medical care. Journal Business Economic Statistics.1983;1:115-126.
Mullahy J. Much ado about two: reconsidering retransformation and the two-part
model in health econometrics. J Health Econ.1998;17:247-281.
Manning WG, Mullahy J. Estimating log models: to transform or not to transform? J Health Econ.2001;20:461-494.
Goldman D, Leibowitz A, Buchanan J. Cost containment and adverse selection in Medicaid HMOs. J Am Stat Assoc.1998;93:54-62.
Ernst ME, Kelly MW, Hoehns JD.
et al. Prescription medication costs. Arch Fam Med.2000;9:1002-1007.
Reissman D. Issues in drug benefit management: have we pushed member co-payments
too far? Drug Benefit Trends.2001;13:24.
Schneeweiss S, Walker AM, Glynn RJ.
et al. Outcomes of reference pricing for angiotensin-converting-enzyme inhibitors. N Engl J Med.2002;346:822-829.