社会项目评估

2013年社会工作者考试全攻略

每日一练历年真题模拟测试章节知识点

21 1. 实验设计和准实验设计|区别在于：是否存在控制z在自然状态下的研究，被观察对象按自己的轨迹发生z在实验研究中，事件被制造出来以便进行研究z如：对服务对象人为分组并采用不用的干预/服务方法，就是实验研究|在社会工作中，自然状态下的研究多用于对现象的一个时点的考察。z如考察一个机构案主的人口学特征z如研究婚姻状态和健康的关系z如机构对服务传递的影响|实验研究多为干预研究，多用于评估考察治疗/服务的效果|实验设计就是通过改变现象研究改变的效果|有助于揭示因果关系zTo establish causality between independent variable (SW intervention/control) and dependent variable (problem or outcome) zExplanatory 分类：Field experiment and laboratory experiment zField experiment: in natural settings, usually zLaboratory experiment: in lab, rare in social work |(True) experiment and quasi-experiment: z

Experiment: designs with equivalent groups produced by random assignment zQuasi-experiment: lacking equivalent groups

•quasi-experimental designs for evaluating programs and practice when practical

constraints in agencies make it impossible to conduct experiments •If participants are placed in groups using some other method such as selecting natural groupings (a classroom or community) 2. Pre-experimental designs |Pre-Experimental Designs：|(1) One-shot case (group) study |只对因变量进行干预后的一次测量，没有说明相关关系|虽说明了时间先后，但不能说明因变量变化，不能排除任何其它原因解释|只能通过直觉判断因变量变化情况|(2) One group pretest-posttest design |比较前后测值|说明了相关性和时间先后，但不能排除自变量以外的其它解释，如：history, maturation, testing, and statistical regression | 如测量社会工作学生在入学时和毕业时对贫困问题重要性的认识。其它解释？| (3) posttest only design with nonequivalent groups X O O1 X O2X O O

22 |比较两组后测值|实际工作中常发生的情况：来不及前测，也无法分等价组|无法排除：如selection biases |以上三种方案，internal validity都不高|但它们也有实际价值，可用于探索或描述性研究|实验设计和准实验设计的internal validity要高于pre-experimental designs 3. 实验设计类型|May not be feasible in real social work setting but can be done in some agency settings |Essential components of experiments: z1) randomly assigning individuals to experimental and control groups z可按抛硬币、随机数码表等方式进行；人数越多，随机分配更有效•例如：申请服务的人和未申请服务的人不算等价组，在申请服务的人中随机分组才可能是等价组z如果没有干预，这两组会一样z虽然无法确保实验组和控制组在所有方面都一样或面临同样的发展过程，但是

随

机分组可帮助实现减少实验组和控制组的差异。z不同于Random sampling (pertains to generalizability) zRandomization or random assignment旨在提高internal validity, 不寻求样本对总体的代表性，而是重在减少实验组和控制组的差异z2) introducing the independent variable (a program or intervention) to experimental group while withholding it from the control group •Multi-group: 2 or more z3) comparing the amount of experimental and control group change on the dependent variable |再次强调：Key element is random assignment of participants to control or comparison groups zSymbol: R = random assignment zi.e., each participant has an equal opportunity to be assigned to each group, AND every possible combination of participants has an equal opportunity to be assigned to each group |类型1：