Health Economics and Financing Programme, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Health Policy Plan. 2012 Jan;27(1):76-83. doi: 10.1093/heapol/czr004. Epub 2011 Jan 27.
A lack of good quality evidence on the effect of alternative social policies in low- and middle-income countries has been recently underlined and the value of randomized trials increasingly advocated. However, it is also acknowledged that randomization is not always feasible or politically acceptable. Analyses using longitudinal data series before and after an intervention can also deliver robust results and such data are often reasonably easy to access. Using the example of evaluating the impact on utilization of a change in health financing policy, this article explains how studies in the literature have often failed to address the possible biases that can arise in a simple analysis of routine longitudinal data. It then describes two possible statistical approaches to estimate impact in a more reliable manner and illustrates in detail the more simple method. Advantages and limitations of this quasi-experimental approach to evaluating the impact of health policies are discussed.
最近，人们强调了在中低收入国家，替代社会政策对效果的高质量证据的缺乏，并且越来越提倡进行随机试验。然而，人们也认识到随机化并不总是可行或在政治上可以接受的。使用干预前后的纵向数据系列进行分析也可以得出可靠的结果，并且这种数据通常很容易获得。本文以评估卫生筹资政策变化对利用的影响为例，说明了文献中的研究如何经常未能解决在简单分析常规纵向数据时可能出现的偏差。然后，它描述了两种可能的统计方法，以更可靠的方式估计影响，并详细说明了更简单的方法。讨论了这种评估卫生政策影响的准实验方法的优缺点。
