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

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Chapter 16 Starting the Data Analysis

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Chapter 16Starting the Data Analysis

Winston Jackson and Norine Verberg

Methods: Doing Social Research, 4e


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


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


Rules for Data Entry (cont’d)

  • Do a column count

    • This will identify the position where each variable will be entered

      VariableColumns

      ID1-3

      Record #4

      Blank5

      Gender6

      Yr of Birth7-8

© 2007 Pearson Education Canada


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


Figure 16.7 Data with Blanks Between Questionnaire Pages

© 2007 Pearson Education Canada


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


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


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


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


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


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


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


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


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


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


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


Appropriate Methods of Analysis by Level of Measurement

© 2007 Pearson Education Canada


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


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


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


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


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