Dr Fong: The ITC Project is the International Tobacco Control Policy Evaluation Project and the report combines data from different ongoing research and surveillance projects. It is really quite massive because the Global Adult Tobacco Survey (GATS) has been done in fourteen tobacco high-burden countries throughout the world and they are going to be doing some additional countries. GATS is more of a surveillance effort looking at representative national samples across the fourteen countries by the WHO and the US CBC and country partners. The ITC Project was created in 2002 before there was an FCTC designed to create an international system for evaluating the yet-to-come tobacco control policies of the FCTC. Although there are some surveillance components， the survey is really focusing on evaluation. It is a cohort study which means you go to the same people over time and because for evaluation， this allows changes at the level of the individuals with changing policies. We can see how those individuals actually responded and whether or not they changed their behavior. We have a whole set of variables we can link across time. If you have repeat cross-sectional which means you have a population at time one and different people at time two， you cannot link those two because you cannot see change. You can only look at it at the very grand mean level.

　　Fong博士：ITC项目即国际烟草控制政策评估项目，报告中包括了正在进行中的研究和监测项目的数据。这一报告相当庞大，因为国际成年人吸烟调查（GATS）是在全球14个烟草负担高的国家开展的，且还将继续在更多的国家开展。GATS更多的是为了监督，通过WHO、美国CBC和各国家的合作伙伴来共同评估这14个国家的有代表性的样本。ITC项目始于2002年，即世界卫生组织烟草控制框架公约（FCTC）制定之前，其目的是在FCTC公布控制烟草政策之前建立一个评估该政策的国际体系。尽管ITC项目具有一些监测内容，但其主要目的是评估。ITC是一项队列研究，这意味着在研究中对同一个体要进行追踪，因为对评估而言，其主要目的是在个体水平体现政策的变化，即面对政策的变化，个体如何作出反应，以及是否改变了自己的行为。我们有一整套可以联系的变量。如果是横断面研究的话，就意味着在某一时间观察了一组人群，在另一时间观察了另一组人群，我们无法将这两个人群相联系，因为我们无法看到变化。我们只能在总体均值的水平来进行观察。