| | |  | | | | Record from Web of Science® | | | | | | |
| For debate - The statistical basis of public policy: A paradigm shift is overdue |
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| Author(s): Lilford RJ, Braunholtz D |
| Source: BRITISH MEDICAL JOURNAL Volume: 313 Issue: 7057 Pages: 603-607 Published: SEP 7 1996 |
| Times Cited: 96 References: 13 |
| Abstract: The recent controversy over the increased risk of venous thrombosis with third generation oral contraceptives illustrates the public policy dilemma that can be created by relying on conventional statistical tests and estimates: case-control. studies showed a significant increase in risk and forced a decision either to warn or not to warn. Conventional statistical tests are an improper basis for such decisions because they dichotomise results according to whether they are or are not significant and do not allow decision makers to take explicit account of additional evidence-for example, of biological plausibility or of biases in the studies. A Bayesian approach overcomes both these problems. A Bayesian analysis starts with a ''prior'' probability distribution for the value of interest (for example, a true relative risk)-based on previous knowledge-and adds the new evidence (via a model) to produce a ''posterior'' probability distribution. Because different experts will have different prior beliefs sensitivity analyses are important to assess the effects on the posterior distributions of these differences. Sensitivity analyses should also examine the effects of different assumptions about biases and about the model which links the data with the value of interest. One advantage of this method is that it allows such assumptions to be handled openly and explicitly, Data presented as a series of posterior probability distributions would be a much better guide to policy, reflecting the reality that degrees of belief are often continuous, not dichotomous, and often vary from one person to another in the face of inconclusive evidence. |
| Document Type: Article |
| Language: English |
| Reprint Address: Lilford, RJ (reprint author), UNIV BIRMINGHAM, BIRMINGHAM B16 9PA, W MIDLANDS ENGLAND |
Addresses:
1. UNIV LEEDS, NUFFIELD INST HLTH, LEEDS LS2 9PL, W YORKSHIRE ENGLAND |
| Publisher: BRITISH MED JOURNAL PUBL GROUP, BRITISH MED ASSOC HOUSE, TAVISTOCK SQUARE, LONDON, ENGLAND WC1H 9JR |
| Subject Category: Medicine, General & Internal |
| IDS Number: VG108 |
| ISSN: 0959-8138 |
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