—Achen’s Rule of Three三个变数就好 * * 参、提出研究设计 ：内在效度与外在效度
* * 两种研究效度 1. 内在效度(internal validity) 本案变量之间因果推论的有效性 (external validity) 本研究案能够放诸四海皆准的程度 * * 影响内在效度的因素 （１）突发事件 （２）成熟 （３）不稳定 （４）先前测试的影响 （５）测量工具的改变 （６）回归（极端值）所造成 （７）选样误差 （８）样本流失 （９）选样误差与成熟交互作用 * * （１）突发事件 发生在前测与后测之间 影响变量的因果推论 两颗子弹与台湾选民投票行为 * * 2004年总统选举前后民众投票意向改变情况 * * （２）成熟 受测者更加成熟与有经验 * * （３）不稳定 母体定义改变 测量工具信度/穩定度差 抽样方式不一致 * * （４）先前測試的影響 前测改变的受测对象的原有属性 绿巨人 * * （５）测量工具的改变 “The government in Washington ought to see it that everyone who want to work can find a job.” Now would you have an opinion on this or not? (If yes): “Do you think the government should do this”? (Welfare) “In general, some people feel that the government in Washington should see to it that every person has a job and a good standard of living. Others think the government should just let each person get ahead on his own.” Have you have been interested enough in this to favor one side over the other? (If yes): “Do you think that the government should see to it that every person has a job and a good standard of living or should it let each person get ahead on his own?” (Welfare) * * （６）回归（极端值）所造成 * * （７）选样误差 电视 语音民调 叩应观众意见 * * （８）样本流失 * * （９）选样误差与成熟交互作用 年龄与城乡差距 * * 肆、测量（略） 以数字代表特性 * * 一、测量的程度 ：仅提供分类，如性别与省籍 ：可以排序、排名，当然，也具有分类的特性 。如，对各县市首长的施政满意度。 ：每一个刻度之间的距离是相同的 。如，温度。 4.