Epistemology and Methods Data Selection, Operationalization, and Measurement May

From Theorie to Empirical Testing! Building on –Research question/puzzle-driven –Existing literature –Model building (concepts, key variables, arguments, hypotheses) –Underlying causality story Now: Operationalization for the purpose of testing –Formulating Variables into Measures –Engage in Observation/Measuring

From Theorie to Empirical Testing! Weaknesses of research design (see also KKV) –Indeterminate research designs more inferences than observations (more explanatory variables than cases) Multicollinearity –Selection Bias –Measurement Errors…

Key decision: determining what to observe Selection and Danger of Bias Violation of key rule: conditional independence Assumption that observations/values assigned to IV are independent of the values of DV IV is correlated with DV (endogenous) DV causes IV (reverse causality)

Random Selection vs. Intentional Selection  In large-n research (universe of cases, random selection)  In small-n research (intentional selection) Random Selection and its limits Powerful: automatically uncorrelated with all variables (controlled experiments: random selection, treatment variables (explanatory variables)) You need to know the universe of cases! In qualitative research: selection bias is more often present!

Selection Bias Comparative study on wars, which wars? The performance of IOs, which IOs? Influence of civil servants /interviewing civil servants, which ones? (e.g. Snow-ball technique in elite interviews) Example (KKV) US investment in developing countries as prime cause for internal violence Selection: Nations with major US investments with great deal of internal violence; nations without major US investments and no internal violence.

Selection on the Dependent Variable Selection should allow for some variation on the DV (key rule) Variation could be truncated: only limited observation of variance on DV that exists in real world Example: Effect of number of accounting courses (IV), salary (DV) –KKV, Figure 4.1 Other examples: –Why do wars occur: only select wars! –What explains trade disputes? Which disputes are being litigated over…

Various relationsships (Geddes)

Selection on the Dependent Variable Geddes Examples: Labor repression significantly affect growth rates Skocpol’s States and Social Revolutions French, Russian and Chinese revolutions (and contrasting cases: Prussia, Japan) “…an assessment of the argument based on a few cases selected from the other end of the DV carries less weight than would a test based on more cases selected without reference to the DV…”

Selection on the Explanatory Variable No inference problem We could limit the generality of our conclusion, or the explanatory variable does have no effect on DV, but we introduce no bias… Other research strategy: controlling for an important IV (focus on other explanatory variables)

Measurement Issues Case studies: (Historian) method of causal imputation/interpretation (not causal inference) Where bias is possibly introduced: –Weighting explanations / IV –Value of primary sources (original purpose of documents) –Bias of secondary sources –Overestimation of rationality of decision-makers –Interpreting unobserved processes (e.g. which data from below was taking up by the top-level? ) Double-check sources (triangulation)

Watch out for! Validity of measurements Do we measure what we think we are measuring? e.g. survey questions? Reliability Applying the same method will yield the same results e.g. survey questions? Can results be replicated?

Replication Data and applied methods (e.g. regression analysis) Sources, secondary literature, direct observation (more difficult: impressions and weighting of factors) Ensure access to material for future researchers (data, unpublished/private records) Use coding sheets/ coding rules

Measuring Political Democracy Bowman et al on “data-induced measurement errors” Challenge of measuring Conceptualization Operationalization by construction of measures Aggregation of measures

Measuring Political Democracy Inaccurate, partial or misleading secondary sources, threat to validity! Remedy: Use of area experts in the coding Example: Coding of Central American Countries in Gasiorowski 1996 Polity IV 2002 Vanhanen 2000 Weak correlation among CA cases! Validity issue! Coders measure different things!

Measuring Political Democracy New coding /index on five dimensions: –Broad political liberties, competitive elections, inclusive participation, civilian supremacy, national sovereignty Coding (0; 0.5; 1) All elements are necessary conditions, not standard aggregation Use of fuzzy-set rules…”weakest score”

Summary: Skepticism! Conceptualization, operationalization and measurement Case selection & samples –Explain your selection of the cases you analyze –Show awareness of the universe of data Measuring –Explain what “proxies” you use for measuring the variable –Think about validity and reliability (how to “improve” or control for bias…)

Next week Carry out the empirical testing (various methods available) Choosing quantitative or/and qualitative methods