Understanding SPSS II
2016-17 Workshop Series
May 25, 2017
Office of Institutional Research (IR)
• Accountability
• Internal
• External
• Visit us at:
https://www.csusb.edu/institutional-research
• Assessment
• Continual Improvement Support
• Surveys and Measures
• Planning
• Enrollment Management/Resource
Allocation
• Decision-making and Policy
Formation
• Research
• Qualitative and Quantitative Research
• Dissemination
IR Staff
• AVP for Institutional Effectiveness and Director of IR
• Muriel Lopez-Wagner
• Assistant Director
• Tanner Carollo
• Institutional Effectiveness Associate
• Joanna Oxendine
• Research Analyst
• Akira Kanatsu
• Research Technicians
• Brandon Aragon, Mariela Monge
• Administrative Support Coordinator
• Monica Villarruel
What is SPSS?
• Statistical analysis software
• Descriptive statistics and frequencies
• T-Tests, ANOVA, correlations, etc.
• Tabulated reports, graphs, and charts.
• Can also be used for data management
SPSS or Excel?
• Some benefits of using SPSS over Excel include:
• Quick and easy access to descriptives
• Variety of charts and graphs
• Flexible pivot tables
• Easy to create subsets
• Easy value labeling
• User friendly with output that is easy to understand
Today’s Topics
• SPSS Syntax
• Merging Datasets
• Custom Tables
• How to Save a File
Syntax
• Syntax can be used as an alternate to Point-and-Click.
• Effective for repetitive tasks.
• Useful for creating reports multiple times.
• Same syntax can be used for different datasets.
Syntax: Rename Variables
• To rename a specific variable, use the following syntax:
• RENAME VARIABLES variable name = new name.
EXECUTE.
• Using Dataset 1, rename TotalGradePointAverage to TOTGPA.
• Highlight your syntax and click the run arrow
• You can also use Ctrl+R as a shortcut.
• Be sure your active dataset is the one you want to run the syntax on.
Syntax: Value Labels
• Enter value labels for Gender where
• 1 = Female
• 2 = Male
• The syntax to create value labels:
• VALUE LABELS Gender
1 ‘Female’
2 ‘Male’.
EXECUTE.
• To add value labels to a string variable, put quotes around the value:
• VALUE LABELS Gender
‘1’ ‘Female’
‘2’ ‘Male’.
EXECUTE.
Syntax: Formats
• To change the current format of a variable, use the FORMATS syntax.
• Round TOTGPA to 2 decimals by adjusting its format:
• FORMATS TOTGPA (F3.2).
EXECUTE.
• The length of string variables can also be adjusted:
• FORMATS variable name (A#).
EXECUTE.
Syntax: Alter Type
• We can alter and adjust the format of variables using ALTER TYPE.
• Change Gender from a numeric variable to a string with a width of 1.
• ALTER TYPE Gender (A1).
EXECUTE.
• To alter from string to numeric:
• ALTER TYPE variable name (F#.#).
Syntax: Compute (with IF statements)
• New variables can be computed using a specific value or from preexisting variables.
• Create a numeric variable called ‘Honors’ that flags students with a
TOTGPA greater than or equal to 3.5.
• First, compute the Honors variable to equal 0. Second, flag those with
TOTGPA greater than or equal to 3.5.
• COMPUTE Honors = 0.
IF TOTGPA >= 3.5 Honors = 1.
EXECUTE.
Syntax: Compute (with IF statements) cont’d
• To create a new string variable, the variable itself must be created
before its values are computed.
• Create a string variable called ‘Class_Standing’ that flags Freshmen
and Sophomores as 1 for Lower Division and Junior and Seniors as 2
for Upper Division.
• STRING Class_Standing (A1).
COMPUTE Class_Standing = ‘1’.
IF Level = ‘Junior’ OR Level = ‘Senior’ Class_Standing = 2.
EXECUTE.
Syntax: ANY Statement
• Instead of using the OR statement, we can use the ANY statement.
• ANY is more compact and efficient.
• Going back to the last example, let’s use the ANY statement in the last
example instead of OR.
• STRING Class_Standing (A1).
COMPUTE Class_Standing = ‘1’.
IF ANY(Level, ‘Junior’, ‘Senior’) Class_Standing = 2.
EXECUTE.
Syntax ANY Statement Cont’d
• In general, the ANY statement has this format:
• ANY(variable, value1, value2, value3,…)
• Translation: IF variable = value1 OR variable = value2 OR variable = value3 …
• ANY(value, variable1, variable2, variable3,…)
• Translation: IF variable1 = value OR variable2 = value OR variable3 = value …
Syntax: Apply Current Syntax to Dataset 2
• Select Dataset 2 to be your active dataset.
• High all syntax (Ctrl+A) and press the run icon.
• If no syntax is highlighted, the entire syntax is run by default.
Merging Datasets
• We can merge two datasets
together by adding cases or
variables.
• There are two ways to merge
datasets in SPSS. Using the top
ribbon select Data -> Merge Files
->:
• 1. Add Cases
• 2. Add Variables
Merging Datasets: Add Cases
• First we will add cases with Dataset
1 being the active dataset.
• Select Dataset 2 to add cases from.
• Check to make sure variable
names, types, and widths are the
same.
• Unpaired variables are variables
that are not in both datasets or do
not match name, type, or width.
Merging Datasets: Add Variables
• Before merging two datasets
together by adding variables, there
should not be duplicate cases in
the second dataset.
• First, identify duplicate cases in
Dataset 3:
• Data - > Identify Duplicate Cases
• Since there are no duplicates, we
can proceed with the merge.
• An error message will appear in the
output if there are duplicate cases
in the keyed table.
Merging Datasets: Add Variables
• We can add variables to our
current dataset by merging
Dataset 3 into number 1 by ID.
• Key variables are used to match
cases within one dataset to
another.
• Check match cases on key
variables and move ID to the key
variables section.
• The keyed table does not have
duplicate key variable values.
Custom Tables
• Custom Tables can be used to
create more complex outputs
than Descriptive Statistics. Drag
and drop variables similar to an
Excel Pivot Table.
• Analyze -> Tables - > Custom
Tables
• Create a table that breaks down
STEM and non-STEM majors by
Gender and Class_Standing.
• Next, add Level to the table.
Custom Tables cont’d
• Click on STEM and open
Summary Statistics.
• Add Column N % and Layer N %
• Categories and Totals
• Change the order of values, add
totals and subtotals
• Paste Syntax for later use:
Saving a File
• File -> Save As
• Save file in different formats (.txt,
.xlsx, .csv, SAS, STATA, etc.)
• Variables – Select specific
variables you want to keep.
Thank You!
• Questions/comments?
• Contact Us
• AD-170
• 909-537-5052
• [email protected]