流行病学研究方法幻灯片1.pptVIP

实验流行病学研究Experimental Epidemiology;横断面研究 监测 生态学研究;James Lind (1716-1794) 维C 缺乏－坏血病 (1747) Vitamin C deficiency--scurvy;Edward Salk; 一、定义 (definition);二、基本原则 (basic principle);The research question cannot be answered by observational studies Earlier observational studies have not answered the research question Existing knowledge is not sufficient to determine clinical or public health policy An experiment is likely to provide an important extension of this knowledge ;三、基本特征 (basic characteristic);四、实验流行病学的类型(types of experimental epidemiology);(一)个体试验 (individual trial);（二）社区试验 (community trial);Field Trial or Field Experiment Effect of Hepatitis B Vaccine Against Hepatitis B ; Community Trial (community intervention trial) Fluoridation of Drinking Water to Prevent Saprodontia;（三）临床试验 (clinical trial); Clinical Trial Therapeutic Efficacy of Drug A;Phases of Clinical Trials (FDA);Phase 3: Effectiveness, Full scale evaluation of treatment; licensing approval From 100 to thousands of people Compare new treatment with current standard Phase 4: Post marketing surveillance, Monitor adverse reactions From hundreds to thousands of people Usually takes place after drug is approved Used to further evaluate long-term safety and effectiveness of new treatment;应该注意的问题 Issues should be paid attention to;现场试验与临床试验比较;现场试验与临床试验比较 Difference Between Filed Trial and Clinical Trial;真实验 true experiment;类实验 quasi-experiment;第二节 研究设计与实施 Design and Execution ;一 明确研究目的 二 研究对象的选择 三 确定实验现场 四 样本大小的确定;四、样本量估计 （estimate the quantity of the samples）;五、随机化分组 （randomization）;简单随机分组 (simple Randomization);Simple Randomization;分层随机分组 (stratified randomization);Stratification Randomization Categorizing subjects into subgroups by specific characteristics Enables researchers to look into separate subgroups to see whether differences exist;整群随机分组 (cluster randomization);