DEVELOPING A CODING SCHEMEDEVELOPING A CODING SCHEME

ANDAND

SETTING UP YOUR SPSS DATA SETTING UP YOUR SPSS DATA FILEFILE

2

DEVELOPING A CODING SCHEME DEVELOPING A CODING SCHEME AND SETTING UP YOUR SPSS AND SETTING UP YOUR SPSS

FILEFILE

The following steps must be taken in the order presented below:

1. Develop a Coding Scheme:

(Ground Rules to be Followed When Coding the Data)

HOW?

– By starting with a blank copy of your survey

(For an example, see the following Faculty Unionization Survey)

3

DEVELOPING A CODING SCHEMEDEVELOPING A CODING SCHEME

(Continued on the next slide)

4

DEVELOPING A CODING SCHEMEDEVELOPING A CODING SCHEME

5

DEVELOPING A CODING SCHEME DEVELOPING A CODING SCHEME AND SETTING UP YOUR SPSS AND SETTING UP YOUR SPSS

FILEFILE

The following steps must be taken in the order presented below:

1. Develop a Coding Scheme

Use a blank survey to:

A. Specify any additional variables that may need

to be added to the data set.

For Example:

6

DEVELOPING A CODING SCHEMEDEVELOPING A CODING SCHEME

Campus: ISU NIU SIU ID____ Deadline: Before After

7

DEVELOPING A CODING SCHEME DEVELOPING A CODING SCHEME AND SETTING UP YOUR SPSS AND SETTING UP YOUR SPSS

FILEFILE

The following steps must be taken in the orderpresented below:

1. Develop a Coding Scheme--use a blank survey to:

A. Specify any additional variables that may need to be added to the data set.

B. Identify your reverse items (items that will have

to be reverse coded before they are used in any

computations and/or analysis).

8

DEVELOPING A CODING SCHEMEDEVELOPING A CODING SCHEME

R R R

R

R

R

Campus: ISU NIU SIUID____ Deadline: Before After

ATTITUDE TOWARD UNIONS:

Liberalism/CONSERVATISM:

9

DEVELOPING A CODING SCHEME DEVELOPING A CODING SCHEME AND SETTING UP YOUR SPSS AND SETTING UP YOUR SPSS

FILEFILEThe following steps must be taken in the order presented

below:

1. Develop a Coding Scheme--use a blank survey to:

A. Specify any additional variables that may need to be added to the data set. B. Identify your reverse items (items that will have to be reverse coded before they are used in any computations and/or analysis). C. Assign variable names to all your variables. D. Specify how you wish to code the values of each

variable.E. Specify how you will code missing values (e.g., non- responses).

A true non-response is ordinarily coded as a blank.

10

DEVELOPING A CODING SCHEMEDEVELOPING A CODING SCHEME

uni1uni2runi3r

uni4rcon1

con2r

con3

con4

con5r

con6r

con7

con8

Campus: ISU=1 NIU=2 SIU=3ID_____ Deadline: Before=0 After=1

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DEVELOPING A CODING SCHEMEDEVELOPING A CODING SCHEME

age

sex

race

marital

rank rankyr

degree

experyr

instyr

leave

tenure

pay

123

456

0 1125

34

0 1

12

34

0 1

123

45

45

123

12

34

1 2 3

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2. Create your new SPSS FILE and define the attributes of your variables following the instructions in your handouts entitled:“Instructions for Creating SPSS Files & Using SPSS to Perform Statistical Analysis” and “SPSS Tutorial—Using the Data Editor.”

Make sure to follow the ground rules you have established in your coding scheme. That is, to designate:

A. Variable Names

B. Variable Labels

C. Value Labels (e.g., for variable gender, 0=Male, 1=Female this is especially important for categorical variables.)

D. User-Missing Values

E. Variable Types (i.e., numeric or string)

F. Variable Formats (maximum number of digits and decimals required for coding the values)

(SPSS FILE “UNIONIZATION CODING EXERCISE_THE FILE SHELL”)

DEVELOPING A CODING SCHEME DEVELOPING A CODING SCHEME AND SETTING UP YOUR SPSS AND SETTING UP YOUR SPSS

FILEFILE

13

G. Column Formats (column width used to display a variable on the screen)

– NOTE: It may be more convenient to assign the same attributes to several variables by copying and pasting the attributes.

3. Code the data into your SPSS file following the ground

rules established in your coding scheme and observed

when creating your SPSS file.

4. Reverse code your reverse items--only after all the coding is

completed (Menu Bar: Transform, Recode into a new var.)

See handout entitled “SPSS Tutorial: Modifying Data Values.”(SPSS FILE “UNIONIZATION CODING EXERCISE_FICTITIOUS DATA”)

DEVELOPING A CODING SCHEME AND DEVELOPING A CODING SCHEME AND SETTING UP YOUR SPSS FILESETTING UP YOUR SPSS FILE

14

5. Compute and print summary/descriptive statistics--e.g., mean, std. dev., min., and max. for metric variables; and frequencies, min., and max. for categorical variables

(Menu Bar: Analyze, Descriptive Statistics)

6. Examine the data and summary statistics (e.g., frequencies, min. & max. values) to spot and correct coding errors.

7. Calculate reliability ONLY for each of your summated multi-item scale and, (a) identify items detracting from reliability, and (b) refine the scale accordingly

(Menu Bar: Analyze, Scale, Reliability Analysis, Statistics--“Inter-item correlations” and “Scale if item deleted”) (SPSS FILE “UNIONIZATION CODING EXERCISE_FICTITIOUS DATA”)

DEVELOPING A CODING SCHEME DEVELOPING A CODING SCHEME AND SETTING UP YOUR SPSS AND SETTING UP YOUR SPSS

FILEFILE

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8. Create a composite/summated variable for each summated multi-item scale

(Menu Bar: Transform, Compute--Target Variable = a mathematical expression)See handout entitled “SPSS Tutorial: Calculating New Data Values.”

(SPSS FILE “UNIONIZATION CODING EXERCISE_FICTITIOUS DATA”)

9. Compute Descriptive Statistics for different subgroups separately

(Menu Bar: Data, Split File, Organize Output by Groups--specify the grouping variable) OR (Menu Bar: Analyze, Compare Means, Means, Dep. List, Indep. List, Select Options, OK)

10. Save and print your SPSS data file (Menu Bar: File, Save As…)11. Analyze the data (Menu Bar: Analyze--select analysis options)

DEVELOPING A CODING SCHEME DEVELOPING A CODING SCHEME AND SETTING UP YOUR SPSS AND SETTING UP YOUR SPSS

FILEFILE

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QUESTIONS

OR

COMMENTS?