220 likes | 311 Views
Research Design Basics Analytical Techniques for Public Service -- Core 2 -- Fall 2009 Week Two Dennis McBride dmcb@u.washington.edu. Two purposes for Tonight:. Have a basic understanding of common research designs and when to use them.
E N D
Research Design BasicsAnalytical Techniques for Public Service -- Core 2 -- Fall 2009Week TwoDennis McBridedmcb@u.washington.edu
Two purposes for Tonight: • Have a basic understanding of common research designs and when to use them. • Have a basic understanding of logic models, when and why to use them.
Basic Considerations for Research Designs • Address the research question. • Research designs as tools. • Objectivity in research.
Address the research question. • There are a number of different research designs that can address any given problem/issue. • However, there can be incorrect designs that are used. This usually results from the design not adequately addressing the research question being asked.
Research designs as tools. • Think of designs as tools. Some tools are better suited for some jobs than others. • You normally use a number of different tools for a given project.
Objectivity in research Pure objectivity in any research project is probably impossible. But this isn’t an either/or issue. The researcher should do the best they can to remain as objective as possible –
Common Research Purposes • Exploration • Description • Explanation From Babbie, The Practice of Social Research.
Exploration • Explore an idea. • Feasibility for further more systematic studies. • further develop methods.
Methods commonly used in exploration • Surveys -- Non-random samples (convenience samples, snowball samples). • Case histories. • In-depth interviews. • Focus groups. • Participant observation, detached observation.
Descriptive Studies • Used to describe aspects/characteristics of a group, population, or some other entity. • Surveys are commonly used but most methods can be used depending upon the question(s) being addressed (e.g., if you want to establish generalizable samples then some kind of random sampling procedure is best).
Explanation • Answers why • Concerned with cause & effect • In program evaluation interest is in determining if, why, and under what conditions an intervention will have an affect on outcomes.
Experimental & Quasi-Experimental Designs • Experimental designs • Quasi-experimental designs • Pre-experimental designs • Campbell, D. T., and Stanley, J. C. Experimental and Quasi-experimental Designs for Research. Chicago: Rand McNally, 1966.
Basic Design Hierarchy for Program Evaluation • Random Assignment (Equivalent groups ) (difference between random selection and random assignment). • Matched Comparison Groups (non-equivalent groups). • Existing Statistics (e.g., compare with vital statistics). • Multiple Time Series (Time series comparison of two counties). • Time Series -- Usually used with existing statistics and looking at changes over time (e.g, teen pregnancy rates before and after family planning clinics). • Pre-post only Designs.
Pre-test/Post-test Only Design How likely is it that you will have sexual intercourse in the next year? 5 4 3 2 1 5. I definitely will 4. I probably will 3. I don’t know 2. I probably will not 1. I definitely will not Risk Pre-test Post-test Time
Control Group Design How likely is it that you will have sexual intercourse in the next year? 5 4 3 2 1 Comparison Treatment Risk Pre-test Post-test Time
Issues in inferring cause. • Correlation • Time order • Nonspurious From Babbie, The Practice of Social Research.
Potential spurious influence I just ran across a clipping that stated “ … individuals receiving swine flu shots were twice as likely to get the seasonal flu than those not receiving swine flu shots.” The article went on to say that the swine flu shots were the causal factor (because it lowered resistance) and suggested not receiving the swine flu inoculation.
Spuriousness Example Getting Swine Flu Risk of Getting Flu Getting Flu
Necessary and Sufficient Conditions • Necessary – A necessary condition for being pregnant is being female (except for sea horses). • Sufficient – A sufficient condition for not passing this course is not turning in the assignments From Babbie, The Practice of Social Research.
Units of analysis • Individuals (usual) • Groups (e.g., demographics, households) • Organizations (e.g., state agencies, schools) • Interactions (e.g., mother child dyads) • Artifacts From Babbie, The Practice of Social Research.
Time Dimension • Cross-sectional Studies (surveys) • Longitudinal Studies • Trend -- Usually focuses on indicators within a population over time within • Cohort – Follows the same group of folks over time • Panel – Following the same folks over time. From Babbie, The Practice of Social Research.
Exercise 1: Design Situations. Identify, the purpose (explore, describe, or explain), whether it is a Nomothetic or ideographic study, what are the units of analysis, and the time dimension (cross-sectional, or longitudinal). If it is longitudinal is it a trend, cohort, or panel? Recommend a plausible design strategy.