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

Chapter 16Starting the Data Analysis

Winston Jackson and Norine Verberg

Methods: Doing Social Research, 4e

16-2 © 2007 Pearson Education Canada

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)


Rules for Data Entry

A. Creating a raw data file (Syntax file in SPSS)1. 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

2. Code any uncoded questions Any open-ended questions or occupational

prestige scores that need to be looked up should be assigned values


Rules for Data Entry (cont’d)

3. 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



4. Enter data with a partner Fewer errors with help of another person

5. 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


Figure 16.7 Data with Blanks Between Questionnaire Pages

PAGE 1 PAGE 2 PAGE 3 PAGE 4

00112435445523 211212333448976999 123232111123212 23411112

00211231231234 322213222122232212 432235333211232 34532432

00314321234443 233445324433321212 332122341122233 23323222

00413444688855 1222221122321233219 234433221222321 34521211

00513335543221 223332221114124211 332111422111212 32121223

00614322345432 231143321122122121 112211222111231 22132454



6. 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.



7. 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



8. 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

9. Use double data entry Can be done to find errors



10. 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

11. Check for errors Check for errors prior to data analysis E.g., using O (letter) instead of 0 (zero)



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



i. 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

ii. 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


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)


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.


Steps in Analyzing Project Data

1. Run and print FREQUENCIES (nominal and ordinal variables) and DESCRIPTIVES (ratio variables) Keep for future reference and reporting results

2. Use RELIABILITY and COMPUTE commands to construct indexes

3. 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)


Steps in Analyzing Data (cont’d)

4. Run analysis for intervening or source of spuriousness models (see Chapter 17)

5. Create summary tables (see Chapter 18)

6. Write your report using appropriate headings (see Chapter 18)


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


Appropriate Methods of Analysis by Level of Measurement

INDEPENDENT VARIABLE

Dependent Nominal Ordinal Ratio

Nominal CROSSTABS CROSSTABS CROSSTABS

DISCRIMINANT

Ordinal CROSSTABS CROSSTABS

SPEARMAN CORR

CROSSTABS

SPEARMAN CORR

DISCRIMINANT

Ratio MEANS

ANOVA

T-TEST

MEANS

ANOVA

T-TEST

CORRELATION

GRAPH

PARTIAL CORR

ANOVA

REGRESSION


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


Tips on Detecting Errors

1. Expect errors Normal part of data analysis

2. Examine error and warning messages carefully The character or symbol creating the

problem will be listed

3. Make certain SPSS is accessing the necessary files

4. Fix first errors first Fix the first error(s) and re-run the job; may

correct all other errors or warnings


Tips on Detecting Errors (cont’d)

5. 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

6. 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)


Tips on Detecting Errors (cont’d)

7. Double check variable list Make sure you are using the appropriate

variable; this is particularly important when you have done recodes for variable

8. 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.

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

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