CONTROLLED COMPARISONS

READING Pollock, SPSS Companion, chs. 4-5

Testing Hypotheses Experimental Designs: The True Experiment: pre-measurement, treatment, post-measurement for “test” and “control” groups The Natural Experiment: external or ascriptive factors (“nature”) define test or control groups Controlled Comparisons: “How else?” and holding rival causes constant Example: Opinions on Gun Control

Support for Handgun Control: Comparing Percentages

Support for Handgun Control: % Within Groups A.Gender not Partisanship ______% in Favor_______ Gender Dems Repubs Female Male B.Partisanship not Gender _______% in Favor_______ Gender Dems Repubs Female Male 60 45

C. Partisanship and Gender ________% in Favor________ Gender Dems Repubs Female Male 40 30

RETHINKING GUN CONTROL __Democrats____Republicans__ Female MaleFemale Male For Agst

The Analytical Challenge(s) 1.Establishing cause-and-effect 2.Considering unobserved (lurking) variables— the “What else?” question 1.Assessing roles of other X variables 2.Inventing alternative explanations for any observed relationship (how might we interpret a positive relationship between poverty and radicalism?)

Looking Ahead and Beyond…. 1.What if all bivariate relationships support the the separate hypotheses? What then? 2.Check relationships among the independent variables: Are they measuring different things? Or the same? 3.Can we identify the relationship between Y and, say, X 1, while controlling for the effects of X 2 and X 3 ?