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Monday, Sept. 17 Measuring effectiveness and other CEA considerations. by Donald S. Shepard, Ph.D. Schneider Institute for Health Policy Heller School, MS 035 Brandeis University Waltham, MA 02454-9110 USA Tel: 781-736-3975 • Fax: 781-736-3965 Web: http://www.sihp.brandeis.edu/shepard
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Monday, Sept. 17Measuring effectiveness and other CEA considerations by Donald S. Shepard, Ph.D. Schneider Institute for Health Policy Heller School, MS 035 Brandeis University Waltham, MA 02454-9110 USA Tel: 781-736-3975 • Fax: 781-736-3965 Web: http://www.sihp.brandeis.edu/shepard E-mail: Shepard@Brandeis.edu 1
Practical information • Teaching assistant: Jsuaya@Brandeis.edu • Administrative assistant: Linda Purrini, Next to library in Heller 781-736-3930 Purrini@Brandeis.edu • Cost of packet: $6.00 2
Measuring Effectiveness and Outcomes, QALYs and DALYs Donald S. Shepard, Ph.D. Schneider Institute for Health Policy Heller School, MS 035 Brandeis University Waltham, MA 02454-9110 USA Tel: 781-736-3975 • Fax: 781-736-3965 Web: http://www.sihp.brandeis.edu/shepard E-mail: Shepard@Brandeis.edu 3
Outline • Types of indexes • Measuring national disease burden • Health status questionnaires 4
Needs for combining length and quality of life • Assessing the disease burden of a country or a region, to see which health problems are greatest, and how one country or region compares with another. • Evaluating a program that may impact both mortality and morbidity. 5
Indexes for combining length and quality of life • Quality Adjusted Life Years, QALYs (Zeckhauser and Shepard, 1976) • Potential Days of Life Lost, PDLLs (Ghana health assessment team, 1980) • Disability Adjusted Life Years, DALYs (World Development Report, 1993) 6
Types of scales for assessing quality of life • Value scale: a measure of preferences on a scale with arbitrary endpoints (example, SF36, scale of 0 to 100). • Utility scale: a measure of preferences on a scale with endpoints of 0 and 1 and spacing consistent with probability theory. 7
Ways of assessing utilities • Probability approach – breakeven probability • Time tradeoff - breakeven time 9
General health question In general, would you say your health is poor, fair, good, very good, or excellent? 1 poor 2 fair 3 good 4 very good 5 excellent 10
Limitation of physical activities Here are a list of activities that you might do during a typical day. How much does your health limit you right now in moderate activities, such as moving a table, pushing a vacuum cleaner, bowling, or playing golf? 1 A lot 2 A little 3 Not at all 11
Limitation of social activities During the past 4 weeks, how much of the time has your physical health or emotional problems interfered with your social activities like visiting with friends or relatives? 1 All of the time 2 Most of the time 3 A good bit of the time 4 Some of the time 5 A little of the time 6 None of the time 12
Time tradeoff • Time tradeoff - find the breakeven time • Suppose we were to live 10 years with an impaired state, I • Instead, we could live Y years with perfect health. • Suppose the the value y would make us just indifferent. • Then the utility of I is y / 10. • E.g., if y is 7, then the utility is 7/10 = 0.70 13
Von Neumann – Morgenstern Utility 1 • Suppose we have a “good” outcome which has a utility of 1 (e.g. living year in perfect health) • Bad outcome has a utility of 0 (e.g. dying at the start of the year) • Intermediate outcome (I) has utility of x (e.g. living with a health limitation), x = u(I) 14
Von Neumann – Morgenstern Utility 2 • Suppose I is indifferent between probability p of good outcome, and 1-p of bad outcome • The utility is von Neumann-Morgernstern if x equals p. 15
Disease burden for gastroenteritis (1): Mortality loss burden per death 18
Disease burden for gastroenteritis (2): Mortality loss burden per case 19
Disease burden for gastroenteritis (3): Morbidity loss burden per case 20
Disease burden for gastroenteritis (4): Total burden per case (days) 21
Disease burden for gastroenteritis (5): Total annual burden per 1000 persons 22
Extensions:Discounting of health impacts • Impacts in future years should be discounted, just as money is discounted • Discounting arises due to “time preference”: • We are anxious to get good things soon. • If we have to wait, them “good” is less highly valued now. 23
Disease burden exercise • Illustrate the calculation of PDLLs from exercise on web site • http://www.sihp.brandeis.edu/shepard 28