How can I show, in the table, categories which have *not* been selected by
respondents?
For versions earlier than 11.5 see Show empty categories in tables.SPS (2 methods are shown) in this section.
For versions 11.5 or over, this option is directly available from syntax of the
CTABLES.
See also the SPSS
FAQ at the University of Texas .
Don't ask if SPSS can do this or that! Ask how
it can be done!
I never expected visitors of this site would ask this question but many
do!
The following brief definition is taken from the SPSS Base User's Guide.
"SPSS is a comprehensive system for analyzing data. SPSS can take
data from almost any type of file and use them to generate tabulated reports, charts, and
plots of distributions and trends, descriptive statistics, and complex statistical
analysis."
The Help menu ;-) This is actually more useful
than many people think. You should, at least once, go through all
the "books" in the Contents Tab of the HELP>TOPICS window. The last
"book" covers Frequently Asked Questions (FAQ) on 10 different topics ranging
from "Opening Data Files" and "Saving Data and Results" to
"Memory and Performance"
The spssbase.pdf file (which you will find using
Help>Syntax Guide>Base or on your SPSS CD).
This file is very useful, it is always open when I work with SPSS. It is the electronic
version of the "Syntax Reference Guide" book which is available from SPSS.
However, I know that users need some time to get used to either versions.
The second CD of version 12 includes pdf versions of the following manuals
A mailing list is managed by a list server (listserv for short). People must register
with the listserv in order to receive a copy of the postings. Each time somebody sends an
email to the list, everybody who has registered receives a copy of the message. When a
person on the list sends a reply to the list, everybody receives a copy. This is a very
effective method of communication. There are usually between 1,000 and 1,200 persons
registered with the SPSSX-L listserv including some SPSS employees (even though the list
is not managed by and does not "belong to" SPSS). The number of postings
averages about 350 per month.
Messages (postings) to the list are archived and may be
searched.
I highly recommend participation to this list to anybody who wants to
improve his/her knowledge of SPSS.
This newsgroup includes more than 23,000 posting. The answer to your question may
already be there.
If you are not familiar with newsreaders such as FreeAgent I would recommend that
you use google
(I do not recommend Outlook). It is very easy to search archives or post messages using
google.
Personally I use a newsreader to send and read posting but I use google to search for
past posting.
The main advantage of using a newsreader is that you can create folders for different
categories of topics and keep interesting articles for future reference.
My general experience is that no company can beat the
"service" that its users are giving to each other via mailing lists or
newsgroups. In other words, if you send a question to both support@spss.com and to the above newsgroup/mailing
list at the same time, the odds are that you will already have received the answer when
SPSS gives it to you. This is not a criticism of the quality of SPSS support.
As a last resort, send me an email. I read all emails but I do not
necessarily answer all of them (there are only 24 hours in a day!). I give preference to
problems which I find interesting or new. If I you do not get a reply, it is not because I
do not "like" you...However, considering that I monitor the SPSSX-L list and the
newsgroup, your best bet is to ask your question through those medium.
You then have many more persons who are likely to answer your question (including some
SPSS employees). Such solutions also become "naturally" available to the whole
community of SPSS'ers. This is consistent with the motto of the defunct dejanews site: Share what you know, learn what you don't.
Note that the
address to subscribe & unsubscribe is different than the address used
to post messages to the list!
To subscribe: send an email to LISTSERV@LISTSERV.UGA.EDU with no subject, no
signature, but only the words:
SUB SPSSX-L <your name>
in the body of the message. For instance if your name is John Doe the body of the
message would contain
SUB SPSSX-L John Doe
After having registered, you will receive an email from the listserv giving the address
to be used to post emails to the list, get copies of earlier posts, unsubscribe, etc. Read
and keep that email for future reference.
To unsubscribe: send an email to LISTSERV@LISTSERV.UGA.EDU with no subject, no
signature, but only the words:
SIGNOFF SPSSX-L
Note that you need to send that email using the same email address to
which you are subscribed. For more information, see the Listserv Reference Card.
For instance sending the command GET SPSSX-L LOG9912 to the LISTSERV would cause the listserv to email you
the full text of postings in December 1999. More commands are described in the Listserv Reference Card. Note that it is also possible
to do searches, for instance one can ask the listserv to forward a copy of all messages
which include the word !ENDDEFINE or the word covariance and were posted between January
1, 2000 and December 1, 2000 (or any other date range).
b) There are two web based archives of SPSSX-L messages:
The best one iswww.listserv.uga.edu
it is quick and easy to use. Postings can be sorted by subject, by date or by
author by month. There is also a search facility.
The second choice (if the first one is not available) is www.marist.edu
(be patient this server is slow; look at the bottom of the page
for the search facility).
c) Unlike a mailing list, one does not "register" to a
newsgroup. One simply go and either post, read or search the newsgroup. The Web site groups.google.com contains
searchable archives of most usenet newsgroups including comp.soft-sys.stat.spss.
Many of the formulas used by SPSS are in Algorithms section of
the Support web site, if you have a recent version of SPSS, this information is also
available
from the CDROM.
The following explanation was posted to the SPSS-X list a few years ago:
"For some historical clarification on the term SPSS as used for the
software package (as opposed to the company), the original name was indeed Statistical
Package for the Social Sciences. When what was to be Release 10 of that package was
released in about 1983, the name was changed to simply SPSS-X (actually, the X was a
superscript). I have seen nothing in any SPSS materials dated later than the early 1980s
that have referred to it as Statistical Package for the Social Sciences or anything other
than just SPSS-X. With Release 4.0, it became just SPSS. There was also SPSS/PC+ for DOS,
and now of course SPSS for Windows, the first release of which was 5.0.
So my understanding is that the term SPSS as applied to the company means
Statistical Product and Service Solutions. As applied to the product or package SPSS, it
now just means SPSS.
David Nichols
Principal Support Statistician and
Manager of Statistical Support
SPSS Inc."
Note that beginning with version 10, SPSS
comes with a defrag utility (This is not the disk utility which comes
with window). From Windows Explorer, right click on an *.spo file and select defrag. This
sometimes significantly reduces the size of *.spo files.
Up to version 10, the regular window version has a maximum of 2^15
- 1 = 32,767
variables and a maximum of 2^31 - 1= 2.15 billion cases.
The student version is limited to 50 variables and 1,500 cases.
Starting with version
10, the limit on the number of variables
has been removed, the only "hard coded" limit is 2.15 billion
variables. This does not mean that it would make sense to work with
millions of variables. It is always more efficient to load only
the variables you currently need.
Here are additional points made by Jon Peck in his
06/05/233 posting to the SPSSX-L list:
In calculating these limits, count one for each 8 bytes or part
>thereof of a string variable. An a10 variable counts as two
>variables, for example.
>Approaching the theoretical limit on the number of variables,
>however, is a very bad idea in practice for several reasons.
>1. These are the theoretical limits in that you absolutely cannot go
>beyond them. But there are other environmentally imposed limits
>that you will surely hit first. For example, Windows applications
>are absolutely limited to 2GB of addressable memory, and 1GB is a
>more practical limit. Each dictionary entry requires about 100
>bytes of memory, because in addition to the variable name, other
>variable properties also have to be stored. (On non-Windows
>platforms, SPSS Server could, of course, face different
>environmental limits.) Numerical variable values take 8 bytes as
>they are held as double precision floating point values.
>2. The overhead of reading and writing extremely wide cases when you
>are doubtless not using more than a small fraction of them will
>limit performance. And you don't want to be paging the variable
>dictionary. If you have lots of RAM, you can probably reach between
>32,000 and 100,000 variables before memory paging degrades
>performance seriously.
>3. Dialog boxes cannot display very large variable lists. You can
>use variable sets to restrict the lists to the variables you are
>really using, but lists with thousands of variables will always be awkward.
>4. Memory usage is not just about the dictionary. The operating
>system will almost always be paging code and data between memory and
>disk. (You can look at paging rates via the Windows Task
>Manager). The more you page, the slower things get, but the
>variable dictionary is only one among many objects that the
>operating system is juggling. However, there is another effect. On
>NT and later, Windows automatically caches files (code or data) in
>memory so that it can retrieve it quickly. This cache occupies
>memory that is otherwise surplus, so if any application needs it,
>portions of the cache are discarded to make room. You can see this
>effect quite clearly if you start SPSS or any other large
>application; then shut it down and start it again. It will load
>much more quickly the second time, because it is retrieving the code
>modules needed at startup from memory rather than disk. The Windows
>cache, unfortunately, will not help data access very much unless
>most of the dataset stays in memory, because the cache will
>generally hold the most recently accessed data. If you are reading
>cases sequentially, the one you just finished with is the LAST one
>you will want again.
(Q first situation) I would like to create a new variable (an ID
variable) which would number each case in my data, starting with 1 and ending with n, the
number of cases in the file. How can I do that?
- Using the menu: select TRANSFORM>COMPUTE then enter id in the
Target Variable text box and $casenum in the Numeric Expression text box. Click OK.(If
nothing happens, select TRANSFORM>RUN PENDING TRANSFORM)
Note that $CASENUM is a system variable. The easiest method to find
the list of all system variables is to open spssbase and search
for "$casenum". (Note that pi is not one of the system variable. Use
COMPUTE
pi=4*ARTAN(1) to get pi.
(Q second situation) What if I do not have any data in my data file
but I would still like to create an ID variable with values between 1 and 10.
(A second situation): This cannot be done using the menu, you need
syntax:
- Using syntax:
INPUT PROGRAM.
LOOP id=1 TO 10.
END CASE.
END LOOP.
END FILE.
END INPUT PROGRAM.
LIST.
(Q third situation) I have many cases with the same ID and would like
to create a new variable where I would number consecutively those cases (within each ID).
(A third situation): See the syntax "Number consecutive cases
within a given ID.SPS" in this section.
Tom lists the following reasons for using an alternative syntax editor:
Some of the advantages are the following:
1) You can create a "code library" that allows you to maintain/re-use code
snippets
2) It has color-coding syntax features
3) It has powerful search-and-replace features (including regular expressions such as
finding tabs, etc.)
4) You can have line numbers display in the left margin, making it easier to keep track
of where you're at!
5) You can have multiple files open at once with tab selectors at the bottom that allow
you to toggle between open documents
6) It has macro capabilities that can record and replay your keystrokes
7) You can setup menu items that run configured tools. For example, I built a small
.exe file in VB that takes any selected text and submits it to SPSS. (In essence, just
like SPSS's syntax editor).
I could probably think of 101 more reasons, but the moral of the story is that I haven't
used the SPSS syntax editor for several months. TextPad is far superior for all of the
above reasons and more. In fact,
you can use it to code for ANY language - Java, HTML/ASP, C++, etc.
Note that it's also useful to set up a new menu item in SPSS that automatically opens
TextPad (with a new, blank .sps document)
For most of our products, you can get the complete product name, version or release
number and date of creation from the "About . . ." dialog box that appears under
the "Help" menu. For example, if you have SPSS for Windows, you might see this:
SPSS for Windows
Release 10.0.0 (September 1999)
You can then write a bibliographic citation as follows:
SPSS for Windows, Rel. 10.0.0. 1999. Chicago: SPSS Inc.
