Introduction to SPSSEdward A. Greenberg, PhD

ASU HEALTH SOLUTIONS DATA LAB

JANUARY 7, 2013

Files can be downloaded from:

http://www.public.asu.edu/~eagle/spss

or (with less typing):

http://tinyurl.com/aa8crpn

Files for this workshop

• SPSS Statistics is a software package used for statistical analysis.

• It is now officially named "IBM SPSS Statistics".

• SPSS uses a graphical user interface.• Most operations are “point and click”.

SPSS Overview

• Installed on most Health Solutions faculty and staff computers

• Available via MyApps for installation on faculty, staff and student computers via University site license

• Run in ASU Online Applications environment (Citrix) via MyApps

• ASU Computing Sites on all campuses

Availability of SPSS

Basic Steps in Data Analysis

• Get your data into SPSS Statistics

SPSS can read data from a variety of sources.

• Prepare your data set for analysis

Set variable attributes, clean your data and apply any needed transformations.

• Select a procedure Select a procedure from the menus to calculate statistics or to create a chart.

• Select the variables for the analysis

The variables in the data file are displayed in a dialog box for the procedure.

• Run the procedure and look at the results

Results are displayed in the Viewer.

• Open a previously saved SPSS Statistics data file

• Read another type of file– Spreadsheet– Database– Text data file

• Enter your data directly in the SPSS Data Editor

Getting Data into SPSS Statistics

The SPSS Data Editor window has two views.• Data View shows a spreadsheet of

cases (rows) and variables (columns).• Variable View displays the metadata

dictionary, where each row represents a variable and shows the variable name, type, and other attributes.

SPSS Data Files

Data View

SPSS Data Editor

Variable View

SPSS Data Editor

Variable Attributes

ATTRIBUTE DESCRIPTION

Name Variable name

Type Data type

Width Number of digits or characters

Decimals Number of decimal places

Label Descriptive variable label

Values Descriptive value labels

Missing User‐defined missing values

Columns Column width

Align Alignment

Measure Measurement level

Role Role assignment

Variable Attributes

VARIABLE NAME• Variable names must be unique.• Variable names may be up to 64

characters in length.• Names can contain letters, numbers, or

special characters. • Names must start with a letter or @, #,

or $.

Variable Attributes

DATA TYPE• Numeric

– 40 character maximum length– Integers or numbers with decimals– Dates and times (various formats)– Other variations of numeric (currency, comma,

scientific notation, etc.)

• String– 32,767 maximum length– Can contain any characters

Variable Attributes

VARIABLE WIDTH• For numeric variables, the width of the

number that is displayed. • String variables can be up to 32,767

characters long.

Variable Attributes

DECIMALS• Number of decimal places displayed for

numeric variables• Allowable values are 0 thru (width-1)

Variable Attributes

VARIABLE LABEL• A descriptive label for a variable• Up to 255 characters in length• Variable labels can contain spaces and

reserved characters that are not allowed in variable names.

Variable Attributes

VALUE LABELS• You can assign descriptive labels for

each value of a variable• Particularly useful if your data file uses

numeric codes to represent non-numeric categories (for example, codes of 1 and 2 for male and female)

• Value labels can be up to 120 characters.

Variable Attributes

MISSING VALUES• Allows you to distinguish between data that are

missing for different reasons. • You can specify up to three discrete (individual)

missing values, a range of missing values, or a range plus one discrete value.

• Missing values are excluded from most calculations.

• By default, an empty cell for a numeric variable is treated as missing.

Variable Attributes

COLUMN WIDTH• The display width of a variable in the Data

Editor• Affects only the display of values in the Data

Editor • Does not change the defined width of a

variable.• Column widths can also be changed in Data

View by clicking and dragging the column borders.

Variable Attributes

ALIGNMENT• Controls the display of data values

and/or value labels in Data View • The default alignment is right for

numeric variables and left for string variables.

• This setting affects only the display in Data View.

Variable Attributes

LEVEL OF MEASUREMENT

LEVEL DESCRIPTION

Nominal Values represent categories with no intrinsic ranking.

OrdinalValues represent categories with some intrinsic ranking.

ScaleValues represent ordered categories with a meaningful metric, so that distance comparisons between values are appropriate.

Variable Attributes

ROLE• Some dialogs support predefined roles

that can be used to pre-select variables for analysis.

• Roles include Input (the default), Target, Both, None and several others.

The Transform menu includes routines which perform transformations on selected variables. These include the following, among others:

Data Transformations

TRANSFORMATION DESCRIPTION

COMPUTECompute values for a variable based on numeric transformations of other variables

COUNTCreates a numeric variable that, for each case, counts the occurrences of the same value(or list of values) across a list of variables

RECODE

Allows you to reassign the values of existing variables or collapse ranges of existingvalues into new values for a new or existing variable

• Most procedures are accessed via the Analyze menu.

• Procedures are grouped according to type, e.g., Reports, Descriptive Statistics, Compare Means, Tables, General Linear Model, and so on.

Running Procedures

Dialog boxes for statistical procedures and charts typically have two basic components:• Source variable list

A list of variables in the active dataset. Only variable types that are allowed by the selected procedure are displayed in the source list.

• Target variable list(s) One or more lists indicating the variables that you have chosen for the analysis, such as dependent and independent variable lists.

Running Procedures

SPSS Viewer

Results are displayed in the Viewer

SPSS Help and Other Resources

SPSS Help Menu

SPSS Help and Other Resources

• Tutorial videos (in Flash format) are available from Central Michigan University at http://calcnet.mth.cmich.edu/org/spss/toc.htm

• Raynald Levesque maintains an excellent SPSS‐related web site with many helpful resources at http://www.spsstools.net/

• The CONHI Data Lab can help you with SPSS: NHI1 391, CONHISTAT@ASU.EDU, (602) 496‐DATA*

• Many excellent books are available on SPSS

* Email probably is the best way to reach us