Presentation on theme: "Research Design Part II: Cross-sectional and Quasi-Experimental Designs Frankfort-Nachmias & Nachmias (Chapter 6 – Cross-Sectional and Quasi-Experimental."— Presentation transcript:
Research Design Part II: Cross-sectional and Quasi-Experimental Designs Frankfort-Nachmias & Nachmias (Chapter 6 – Cross-Sectional and Quasi-Experimental Designs) Gerring (Chapter 8) Campbell and Stanley, “Experimental and Quasi-Experimental Designs for Research.” (remainder) King, Keohane and Verba (Chapter 5, sections ) Applications Stack, S. and Gunlach, J. (1992) “The Effect of Country Music on Suicide.” Social Forces 71: 211–18.“The Effect of Country Music on Suicide.” Lawrence S. Rothenberg; Mitchell S. Sanders, “Severing the Electoral Connection: Shirking in the Contemporary Congress.” American Journal of Political Science, Vol. 44, No. 2. (Apr., 2000), pp (Difference-in- difference) Severing the Electoral Connection: Shirking in the Contemporary Congress.
Writing a Literature Review Typical format for research article Introduction Literature Review Theory Research Design Empirical Analysis and Results Conclusion
Writing a Literature Review Purpose of literature review Inform reader of prior relevant work Persuade reader that your work is important (justify your research)
Possible Justifications for Your Research New question, new theory New question, existing theory Old question, new theory Old question, conflicting theories Old question, conflicting findings Old question, new methods Old question, new data
Literature Review Don’ts Don’t (just) provide a chronological listing of article summaries Don’t provide every detail of every study
Literature Review Do’s Organize your discussion of the literature in a way that reflects and supports the justification for your research Provide more detail for seminal studies, less detail (or simply a citation) for less cited studies For questions that have been studied extensively, it is not necessary to cite every study End your literature review with a summary and critique that justifies your research
Literature Review Assignment Approx pages, double-spaced Due November 2nd
How to Identify the Relevant Literature Use electronic databases and keyword searches (Google Scholar, JSTOR) Prioritize: Articles Articles published in highly-ranked journals Recently published articles Seminal articles Number of articles: 10-20?
Quasi-experimental and Cross- Sectional Designs What are they? Quasi-experimental – study of more than one sample (often over period of time) Cross-sectional – Analysis of a single sample (lacks random assignment, temporal variation, and manipulation); but includes comparison groups Pre-experimental – Cross-sectional, with no comparison group; causal inference impossible
Quasi-experimental and Cross- Sectional Designs Why? Property-disposition relationship vs. Stimulus-response relationship
Pre-Experimental Designs One-Shot Case Study One group No variation in independent variable X O
Pre-Experimental Designs Example: Dependent variable: Americans’ support for campaign finance reform Independent variable: Watergate scandal Data: 1976 survey of American adults; examine mean level of support
Cross-Sectional Designs Static-Group Comparison Design Two groups – observed at one time Allows variation in the independent variable X O 1 O 2
Elaboration of Static Group Comparison Design Correlational / Cross-Sectional Designs X1 O 1 X2 O 2 X3 O 3 X4 O 4 Xi O i Problems with correlational/cross-sectional designs?
Example: Wine and Health Hypothesis: Drinking wine causes individuals to be healthier (esp. heart) Existing studies: compared the health of wine drinkers to the health of those who do not drink wine: Research design X 1 (Wine drinkers) O 1 (Health) X 2 (Non-drinkers) O 2 (Health)
Controlling for Affluence Research design: X 1 (Affluent Wine drinkers) O 1 (Health) X 2 (Affluent Non-drinkers) O 2 (Health) X 3 (Poor Wine drinkers) O 3 (Health) X 4 (Poor Non-drinkers) O 4 (Health)
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Quasi-Experimental Designs Contrasted Groups Design Multiple groups, based on some categorical variable Observed at one point in time (similar to cross-sectional) O1 O2 O3 O4 Oi Problems with contrasted groups designs?
Quasi-Experimental Designs One-Group Pretest-Posttest Design One group Allows variation in the independent variable O1 X O2
Elaborations of the One-Group Pretest- Posttest Design Time Series Designs simple vs. extended O 1 …O k X O k+1 …O m k = # of pretest observations m = total # observations Or (“equivalent time samples design”) X 1 O 1 X 2 O 2 X 3 O 3 … X m O m
Nonequivalent Control Group Design No random assignment O 1 X O 2 O 3 O 4 or O 1 X 1 O 2 O 3 X 2 O 4
Control Series Designs Addition of second (control) group to time series design (CS: “multiple time series design”) O1 O2 O3 X1 O4 O5 O6…… O7 O8 O9 X2 O10 O11 O12……
Panel Designs Repeated observations of the same units over time Also goes by: Pooled time-series design Pooled cross-sectional time-series design
The Effect of Sanctioning in the TANF Program
Donahue and Levitt Hypothesis: The (legal) availability of abortion in a state is negatively related to the crime rate (many years later). O1 O2 O3 X1(early legalization) O4 O5 O6… O7 O8 O9 X2 (legalize 1973) O10 O11 O12…
Gerring’s Criteria for Research Design Plentitude (N) Boundedness (relevant cases) Comparability (descriptive/causal) Independence Representativeness Variation (X, Y, X&Y) Analytic Utility (of the sample) Replicability Mechanism Causal Comparison
KKV – Overcoming Common Problems Omitted Variable Bias Inclusion of Irrelevant Variables Endogeneity Assigning Values of the IV’s Controlling the Research Situation
Does Country Music Cause Suicide?
Stack & Gundlach Hypothesis: There is a positive relationship between exposure to country music and suicide rates Research design: X 1 (no country music) O 1 (suicide rate) X 2 (1 station) O 2 (suicide rate) X 3 (2 stations) O 3 (suicide rate) X 4 (3 stations) O 4 (suicide rate) X i ( etc.) O i (suicide rate)
Stack & Gundlach Findings: 51% of the variation in urban white suicide rates can be explained by variation in airtime devoted to country music Internal Validity?
O 1A Retired A O 4A O 2B SW-Office B O 5B O 3C Returned C O 6C
Regression Discontinuity Designs Example: What is the effect of an award on later achievement? (from CS)
Regression Discontinuity Designs Example: What is the effect of an award on later achievement? (from CS) Inferential challenge: Award recipients are likely to do well anyway, even without the award, because criteria for receiving award also predict future success
A regression discontinuity design is appropriate for any research design in which the assignment of the treatment is determined by a continuous variable that is also related to the outcome of interest.
Ludwig and Miller, 2007
Head Start Head Start is a federal program that provides comprehensive education, health, nutrition, and parent involvement services to low- income children and their families. Head Start began in 1965 Local nonprofits/education agencies must apply to federal government to be a Head Start provider
Head Start Research Question: What is the effect of Head Start on health/well-being of former participants? What problems might we encounter if we were to conduct the following study: X O (where X = Head Start participation) O
Ludwig and Miller, 2007 OEO and application assistance to poor counties in 1965 “Treatment” group – 300 poorest counties that received head start application assistance “Control” group – 228 poor counties that did not