SPSS Statistics is a software package used for statistical analysis. Long produced by
SPSS Inc., it was acquired by IBM in 2009. The current versions are officially named
IBM SPSS Statistics. Companion products in the same family are used for survey authoring
and deployment, data mining, text analytics, and collaboration and deployment.
The software name stands for Statistical Package for the Social Sciences, reflecting the original
market, although the software is now popular in other fields as well, including the health
sciences and marketing.
Overview SPSS is a widely used program for statistical
analysis in social science. It is also used by market researchers, health researchers,
survey companies, government, education researchers, marketing organizations, data miners, and
others. The original SPSS manual has been described as one of "sociology's most influential
books" for allowing ordinary researchers to do their own statistical analysis. In addition
to statistical analysis, data management and data documentation are features of the base
software. Statistics included in the base software:
Descriptive statistics: Cross tabulation, Frequencies, Descriptives, Explore, Descriptive
Ratio Statistics Bivariate statistics: Means, t-test, ANOVA,
Correlation, Nonparametric tests Prediction for numerical outcomes: Linear
regression Prediction for identifying groups: Factor
analysis, cluster analysis, Discriminant The many features of SPSS Statistics are accessible
via pull-down menus or can be programmed with a proprietary 4GL command syntax language.
Command syntax programming has the benefits of reproducibility, simplifying repetitive
tasks, and handling complex data manipulations and analyses. Additionally, some complex applications
can only be programmed in syntax and are not accessible through the menu structure. The
pull-down menu interface also generates command syntax; this can be displayed in the output,
although the default settings have to be changed to make the syntax visible to the user. They
can also be pasted into a syntax file using the "paste" button present in each menu. Programs
can be run interactively or unattended, using the supplied Production Job Facility. Additionally
a "macro" language can be used to write command language subroutines, and a Python programmability
extension can access the information in the data dictionary and data and dynamically build
command syntax programs. The Python programmability extension, introduced in SPSS 14, replaced
the less functional SAX Basic "scripts" for most purposes, although SaxBasic remains available.
In addition, the Python extension allows SPSS to run any of the statistics in the free software
package R. From version 14 onwards, SPSS can be driven externally by a Python or a VB.NET
program using supplied "plug-ins". SPSS Statistics places constraints on internal
file structure, data types, data processing, and matching files, which together considerably
simplify programming. SPSS datasets have a two-dimensional table structure, where the
rows typically represent cases and the columns represent measurements. Only two data types
are defined: numeric and text. All data processing occurs sequentially case-by-case through the
file. Files can be matched one-to-one and one-to-many, but not many-to-many.
The graphical user interface has two views which can be toggled by clicking on one of
the two tabs in the bottom left of the SPSS Statistics window. The 'Data View' shows a
spreadsheet view of the cases and variables. Unlike spreadsheets, the data cells can only
contain numbers or text, and formulas cannot be stored in these cells. The 'Variable View'
displays the metadata dictionary where each row represents a variable and shows the variable
name, variable label, value label(s), print width, measurement type, and a variety of
other characteristics. Cells in both views can be manually edited, defining the file
structure and allowing data entry without using command syntax. This may be sufficient
for small datasets. Larger datasets such as statistical surveys are more often created
in data entry software, or entered during computer-assisted personal interviewing, by
scanning and using optical character recognition and optical mark recognition software, or
by direct capture from online questionnaires. These datasets are then read into SPSS.
SPSS Statistics can read and write data from ASCII text files, other statistics packages,
spreadsheets and databases. SPSS Statistics can read and write to external relational
database tables via ODBC and SQL. Statistical output is to a proprietary file
format for which, in addition to the in-package viewer, a stand-alone reader can be downloaded.
The proprietary output can be exported to text or Microsoft Word, PDF, Excel, and other
formats. Alternatively, output can be captured as data, as text, tab-delimited text, PDF,
XLS, HTML, XML, SPSS dataset or a variety of graphic image formats.
SPSS Statistics Server is a version of SPSS Statistics with a client/server architecture.
It had some features not available in the desktop version, such as scoring functions.
Versions and ownership history The software was released in its first version
in 1968 as the Statistical Package for the Social Sciences after being developed by Norman
H. Nie, Dale H. Bent, and C. Hadlai Hull. Those principals incorporated as SPSS Inc.
in 1975. Early versions of SPSS Statistics were designed for batch processing on mainframes,
including for example IBM and ICL versions, originally using punched cards for input.
A processing run read a command file of SPSS commands and either a raw input file of fixed
format data with a single record type, or a 'getfile' of data saved by a previous run.
To save precious computer time an 'edit' run could be done to check command syntax without
analysing the data. From version 10 in 1983, data files could contain multiple record types.
SPSS Statistics versions 16.0 and later run under Windows, Mac, and Linux. The graphical
user interface is written in Java. The Mac OS version is provided as a Universal binary,
making it fully compatible with both PowerPC and Intel-based Mac hardware.
Prior to SPSS 16.0, different versions of SPSS were available for Windows, Mac OS X
and Unix. The Windows version was updated more frequently and had more features than
the versions for other operating systems. SPSS Statistics version 13.0 for Mac OS X
was not compatible with Intel-based Macintosh computers, due to the Rosetta emulation software
causing errors in calculations. SPSS Statistics 15.0 for Windows needed a downloadable hotfix
to be installed in order to be compatible with Windows Vista.
SPSS Inc announced on July 28, 2009 that it was being acquired by IBM for US$1.2 billion.
Because of a dispute about ownership of the name "SPSS", between 2009 and 2010, the product
was referred to as PASW. As of January 2010, it became "SPSS: An IBM Company". Complete
transfer of business to IBM was done by October 1, 2010. By that date, SPSS: An IBM Company
ceased to exist. IBM SPSS is now fully integrated into the IBM Corporation, and is one of the
brands under IBM Software Group's Business Analytics Portfolio, together with IBM Algorithmics,
IBM Cognos and IBM OpenPages. See also
Comparison of statistical packages Data mining
Data processing gretl – an open source alternative that
can import SPSS data files R Commander – A GUI for the R programming
language Rkward – an open source alternative based
on the R programming language, designed for and integrates with the KDE desktop environment
PSPP – an open source alternative SPSS Modeler
Notes
References Argyrous, G. Statistics for Research: With
a Guide to SPSS, SAGE, London, ISBN 1-4129-1948-7 Levesque, R. SPSS Programming and Data Management:
A Guide for SPSS and SAS Users, Fourth Edition, SPSS Inc., Chicago Ill. ISBN 1-56827-390-8
SPSS 15.0 Command Syntax Reference 2006, SPSS Inc.,
Chicago Ill. Wellman, B. "Doing It Ourselves: The SPSS
Manual as Sociology's Most Influential Recent Book." pp. 71–78 in Required Reading: Sociology's
Most Influential Books, edited by Dan Clawson. Amherst: University of Massachusetts Press,
1998. ISBN 978-1-55849-153-3 External links
Official website Raynald Levesque's SPSS Tools – library
of worked solutions for SPSS programmers Archives of SPSSX-L Discussion – SPSS Listserv
active since 1996. Discusses programming, statistics and analysis
UCLA ATS Resources to help you learn SPSS – Resources for learning SPSS
UCLA ATS Technical Reports – Report 1 compares Stata, SAS, and SPSS against R.
Using SPSS For Data Analysis – SPSS Tutorial from Harvard
SPSS Community – Support for developers of applications using SPSS products, including
materials and examples of the Python and R programmability features