Chapter 16 Starting the Data Analysis

1. Chapter 16Starting the Data Analysis Winston Jackson and Norine Verberg Methods: Doing Social Research, 4e

2. Analyzing Data with a Computer • Requires statistical software program • Appendix A provides guidelines for using Statistical Package for the Social Sciences, known simply as SPSS • See textbook for step-by step instructions on using SPSS for Windows (Versions 10 to 14) • Labs are available with this text to provide additional learning activities for students using SPSS (www.pearsoned.ca/text/jackson-methods) © 2007 Pearson Education Canada

3. Rules for Data Entry A. Creating a raw data file (Syntax file in SPSS) • Give each case an ID number. • Number questionnaires or data-collection forms, starting with 001 (or 0001 if more than 1000 cases) on the top right-hand corner. • The ID number is used to link questionnaire with data in case errors are found • Code any uncoded questions • Any open-ended questions or occupational prestige scores that need to be looked up should be assigned values © 2007 Pearson Education Canada

4. Rules for Data Entry (cont’d) • Do a column count • This will identify the position where each variable will be entered Variable Columns ID 1-3 Record # 4 Blank 5 Gender 6 Yr of Birth 7-8 © 2007 Pearson Education Canada

5. Rules for Data Entry (cont’d) • Enter data with a partner • Fewer errors with help of another person • Note new page with blanks • Errors can be more easily identified if you leave a blank to mark a new page of the questionnaire • On Figure 16.7 (next slide), it is evident that there is an error on the fourth line • Can go back to case 004, and re-enter data from page 2 © 2007 Pearson Education Canada

6. Figure 16.7 Data with Blanks Between Questionnaire Pages © 2007 Pearson Education Canada

7. Rules for Data Entry (cont’d) • Simplify missing value codes • Where possible use a 9, 99, or 999 to indicate situations where a respondent refused to answer a question. • When something is left out but it means zero, use a zero. • In 9-point Likert scales use the 0 to indicate a missing question. © 2007 Pearson Education Canada

8. Rules for Data Entry (cont’d) • Document research decisions • If a response is in doubt (two numbers circled, two answers when only one was asked for), flip a coin to determine which response will be taken • Circle in red and write your initials next to the decision © 2007 Pearson Education Canada

9. Rules for Data Entry (cont’d) • Code for information not on questionnaire • When more than one person is coding un-coded data, it is a good idea to enter a code for each data entry person; in interviews, code the interviewers. If systematic differences occur one can then quickly identify whose questionnaires belong to which person • Use double data entry • Can be done to find errors © 2007 Pearson Education Canada

10. Rules for Data Entry (cont’d) • Save the data • If entered in SPSS, save it as an .sps file • To do so, SPSS will ask if you want to save the file, when you click yes, it is saved as an .sps file • Check for errors • Check for errors prior to data analysis • E.g., using O (letter) instead of 0 (zero) © 2007 Pearson Education Canada

11. Rules for Data Entry (cont’d) B. Point-and-Click Raw Data Entry • Click on File/New/Data • Move cursor to the cell you wish to start with (the cell will be highlighted) and enter the data for each variable, moving across the row • The value will show on the screen © 2007 Pearson Education Canada

12. Rules for Data Entry (cont’d) • To insert a new case • Position the cursor on the case below where you want to insert the new case • On the toolbar, click Data/Insert Case • To insert a new variable • Position the cursor on the variable following the spot where you want to insert the new variable • On the toolbar, click on Data/Insert Variable • Enter data for all the cases © 2007 Pearson Education Canada

13. Creating and Saving an SPSS.SAV File • For modest to large surveys: • Use Syntax Editor to enter commands to define variables, attach labels, and indicate missing value codes • To begin, click File/New/Syntax • To process commands, click on Run • See sample syntax file in Box 16.1 (next slide) • For small surveys (10–15 variables) • Use point-and-click direct-entry method • To begin, click File/New/Data (see pp. 431–434) © 2007 Pearson Education Canada

14. Box 16.1 Sample Syntax Commands to Create an SPSS System File Title system file creation, Social Science Faculty Review, Winston. Data list file = ‘C:\oia\sscience\social science data.SPS’ / id 1-5 v1 8 v2 9 v3 10 v4 12 v4.a to v4.7 13-19 v5 20 v6 22 v8 23 v9.1 to v9.6 24-29 v10 to v12 30-32 v13 34 v16 35 v17 36 v18.1 to v18.5 37-41. variable labels id “identification number” [label up to 40 characters] /v1 “Year of Graduation” /v2 “Program” /v18.5 “Quiet Study Space”. value labels [each label limited to 20 characters] /v1 0 “1995 or earlier” 1 “1996” 2 “1997” 3 “1998” 4 “1999” 5 “2000” 6 “2001” 7 “2002” 8 “2003” /v2 1 “Major” 2 “Advanced Major” 3 “Honours” /v4.1 to v4.5 0 “No” 1 “Yes”. missing values v1, v2, v3, v4, v4.1 to v4,5, v5, v6, v8, v13 (9) /v4.5, v4.6, v9.1 to v9.6, v10 to v12, v16, v17, v18.1 to v18.5 (0). Frequencies var = v1. © 2007 Pearson Education Canada

15. Steps in Analyzing Project Data • Run and print FREQUENCIES (nominal and ordinal variables) and DESCRIPTIVES (ratio variables) • Keep for future reference and reporting results • Use RELIABILITY and COMPUTE commands to construct indexes • Select appropriate procedures for analysis • May need to RECODE some variables (create a new variable by adding the letter “r” to the name of the original variable) © 2007 Pearson Education Canada

16. Steps in Analyzing Data (cont’d) • Run analysis for intervening or source of spuriousness models (see Chapter 17) • Create summary tables (see Chapter 18) • Write your report using appropriate headings (see Chapter 18) © 2007 Pearson Education Canada

17. The 3M Approach 3M is a way to remember how to decide which procedure to use to analyze relationships • Model: >X  >Y • Measurement: Nominal, Ordinal, Ratio • Method (choice depends on level of measurement; see Table 8.18, next slide): • CROSSTABS • MEANS • CORRELATIONS © 2007 Pearson Education Canada

18. Appropriate Methods of Analysis by Level of Measurement © 2007 Pearson Education Canada

19. Getting Errors and Warnings • If you are using the Syntax method of entering SPSS commands, expect to get errors and warnings when running SPSS jobs • SPSS has error checking routines that help you identify the error immediately © 2007 Pearson Education Canada

20. Tips on Detecting Errors • Expect errors • Normal part of data analysis • Examine error and warning messages carefully • The character or symbol creating the problem will be listed • Make certain SPSS is accessing the necessary files • Fix first errors first • Fix the first error(s) and re-run the job; may correct all other errors or warnings © 2007 Pearson Education Canada

21. Tips on Detecting Errors (cont’d) • Stuck? Re-enter the command line • Sometimes we cannot see an error (e.g., O (capital letter) instead of 0 (number) [as in v1O versus v10] • Just re-enter the line, and run again • Examine results on screen before sending to a printer • Sometimes we make mistakes that are obvious when we see them (meant to use a re-coded variable for a CROSSTAB, but used ratio level variable by mistake) © 2007 Pearson Education Canada

22. Tips on Detecting Errors (cont’d) • Double check variable list • Make sure you are using the appropriate variable; this is particularly important when you have done recodes for variable • Check for a premature FINISH command • Forgetting to remove/move a FINISH command when editing a syntax file would result in the part of the job appearing before the finish command being run. • Make sure it’s at the end of the file. © 2007 Pearson Education Canada