Designing Social Inquiry Understanding What to Avoid Jaechun Kim

In previous class, we discussed how we should design our research… how to select our cases… Today, we will discuss things we need to avoid when we make inferences…when we measure variables…

Making Observations - Two criteria for judging the soundness of measurement Un-biasedness - validity Efficiency - reliability… Remember dart-throwing example… ! Increase reliability (efficiency) and reduce bias – that is the goal that you should pursue when you measure your variables…

Types of Measurement Nominal measurement Observations are grouped into a set of categories Presidential system vs. Parliamentary system or… Ordinal measurement Observations are grouped into categories that have ordering schemes Examples?? Countries with degree of industrialization Interval measurement – continuous variables… Example – annual economic growth rate Ethnicity in the US - nominal or ordinal measurement??

p. 153 Use the measure that is appropriate to your theoretical purposes… !

Use measurement made by other researchers for entirely different purposes in order not to craft your variables to justify your hypotheses… e.g., Democratic Peace scholarship uses Polity data set Polity IV Project Grouping error.. What is it? P. 153 Effect of Age on Hours of Sleep Needed… Young-aged group, middle-aged, old-aged groups… Why is it problematic??

Measurement Error… p. 155 on… Don’t worry too about the parts on nonsystematic and systematic measurement error. Just browse the parts on these subjects in KKV…!!! Systematic measurement error What is it? Consequence? It will bias descriptive inference (But systematic measurement error that affects all units by the same constant amount causes no bias in causal inference…)

Nonsystematic Measurement Error What is it? Nonsystematic measurement error in the DV  Consequence? Does not bias the usual estimate of the causal effect, but it does make the estimate less efficient

p. 161 figure here!

p. 165 figure here!

Problem of Omitting Relevant Variables What if we fail to include relevant variables? It will bias our inference in general… e.g., campaign spending  number of votes cf. incumbent advantage What if incumbency does not have any effect on DV? No bias What if incumbency affects both our include IVs and DV? Not controlling for incumbent advantage would cause bias e.g. repressive regime  coup cf. economic conditions

Then, should we include every variable? P. 173 Increase in oil price  Public perception about energy shortage Should include TV coverage of oil price?

How do we cope with this problem? Importance of “sound theoretical model” p. 172 Think about “trade-off” between theoretical parsimony and explanatory breadth…!

Examples of Omitted Variables Bias p.176 Education  Political Participation Two possible omitted variables Political involvement of parents Race* P.177 importance of sound theoretical model!

pp Impact of summit meetings  Cooperation between the USSR and US Any antecedent variables? Econ interests or military interests?? Trust? Convergence of geopolitical ambitions? Any other domestic political reasons? Trade-off issue… p. bottom of 178

Problem of Endogeneity This problem occurs when the values of EVs or IVs take on are a consequence, rather than a cause, of DV… Examples P. 186 Constituency services  Votes No real positive evidence supporting this. Why?

Max Weber’s The Protestant Ethic and the Spirit of Capitalism What is Weber’s causal hypothesis? What’s wrong with this? P. 191 Causal Impact of Ideas… Ideas can be consequences of policy… P. 192 Halpern (1993) What is her causal hypothesis?

Stalinist planning doctrine (idea)  economic policies after WWII Alternative hypothesis? Soviet military might and influence Counterfactual claim of this hypothesis? China and Yugoslovia??

pp , the last paragraph What is the research question of the authors (Verba, Schlozman, and Brady)? What is their causal hypothesis? Going to church  Political Participation Why can it be problematic? How did the authors resolve this ‘endogeneity’ problem?