Data Lab # 3 June 4, 2008 Ivan Katchanovski, Ph.D. POL 242Y-Y

2 Cross-Tabulation Analysis: Example Research Hypothesis: Canadians are more confident in NAFTA than Americans are Dataset: 2000 World Values Survey Questionnaires: 2000 World Values Survey – Canada and US Dependent variable – Confidence in NAFTA (v160e) Independent variable: – Nation (v2)

3 Transforming Variables: Missing Values Recode the following v160e values, which are not relevant to the hypothesis, into missing: “Not asked,” “NA,” “DK” (Do not Know) SPSS recoding command: – Transform/Recode into Different Variables – SPSS “Old and New Values”: -4=System missing (eliminates “Not asked”) Range from 8 to 9=System missing (eliminates “NA” & “DK” – Or define -4, 8, and 9 as missing in “Missing” column

Collapsing/Recoding Values Collapse /recode the following v160e values into two values (Dummy variable) – Range from 1 to 2 = 1 (Combines “Great deal” & “Quite a lot” into one value (Confident) Range from 3 to 4 = 0 (Combines “Not very much” & “None at all” into one value (Not confident) Label values of the new variable: – 1 “Confident” – 0 “Not confident” 4

Transforming Variables: Selecting Canada and US samples Recode all v2 values, except 12 “Canada” and 11 “US,” into system-missing SPSS recoding command – Transform/Recode into Different Variables – SPSS “Old and New Values”: 12=1 11=0 “All other values”=“System missing” Label values of the new variable: – 1 “Canada “ – 0 “US” 5

Cross-Tabulation Analysis: SPSS Command SPSS Command: – Analyze=Descriptive Statistics-Crosstabs – “Row” box: select recoded dependent variable (confidence in NAFTA) – “Column” box: select recoded independent variable (nation) – “Cells” Option: Column percentages Interpretation: – Canadians and Americans do not differ significantly in terms of their confidence in NAFTA – The research hypothesis is not supported 6

Bar Chart SPSS Commands: – Charts-Legacy dialogs-Bar-Simple-Define (Summaries for groups of cases) – Select “Other statistics” and select the recoded dependent variable into “Variable” box – “Change statistic”-Percentages Inside – Low: 1; High: 1 (Selects “Confident” value of the recoded dependent variable – Select the recoded independent variable to “Category Axis” box – Open Chart Editor: Select chart-Edit-SPSS Chart Object-Open – In Chart Editor: Options-Title – In Chart Editor: Elements-Show Data Labels 7

Controlled Comparisons Example: Control for labor union membership (v42) – Specify -4 (“Not asked”) as missing in “Missing” column SPSS Command: – Analyze=Descriptive Statistics-Crosstabs – “Row” box: select recoded dependent variable (confidence in NAFTA) – “Column” box: select recoded independent variable (nation) – “Layer” box: select control variable (v42) – “Cells” Option: Column percentages 8

Line Chart SPSS Commands: – Charts-Legacy dialogs-Line-Multiple-Define (Summaries for groups of cases) – Select “Other statistics” and select recoded dependent variable into “Variable” box – “Change statistic”-Percentages Inside – Low: 1; High: 1 (Selects “Confident” value of the recoded dependent variable – Select the recoded independent variable to “Category Axis” box – Select the recoded control variable to “Define Lines by” box – Open Chart Editor: Select chart-Edit-SPSS Chart Object- Open 9

Interpretation Canadians and Americans express different levels of confidence in NAFTA depending on their union membership Canadian union members (36%) have somewhat lower level of confidence in NAFTA compared to the American union members (40%) Canadians who do not belong to labor unions (44%) do not differ significantly in their level of confidence in NAFTA compared to Americans who do not belong to unions (43%) The line chart shows an interactive type of relationship because the relationship between confidence in NAFTA and country depends on the value of the control variable (labor union membership) The research hypothesis is not supported 10