Quantcast

Horizontal or vertical file structure for repeated measures

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

Horizontal or vertical file structure for repeated measures

Karen Harker
I have inherited a set of SPSS files for several ongoing clinical trials, some of which involve numerous follow-up assessments.  The files for each of the assessments are in a horizontal file structure with separate sets of variables for each of the follow-ups (i.e. dep01_f1 for follow-up 1, dep01_f2 for follow-up #2, etc.).  This has resulted in data sets that are fairly shallow (<100 records) but quite wide (>3000 variables).  Eventually, the researcher will be wanting to do multilevel modeling, in addition to time-series analysis.

I come from a database management background with only limited statistical analysis experience.  I'm uncomfortable with the horizontal file structure...it goes against the grain of my RDBMS training.  Furthermore, I've read that SAS (and SPSS?) needs to have the data in vertical structure for mixed-method analysis.  Before I propose that the data be converted to vertical file structure, I would like to know if there are other considerations that make the horizontal structure better?

Thanks.


Karen R. Harker, MLS
UT Southwestern Medical Library
5323 Harry Hines Blvd.
Dallas, TX  75390-9049
214-648-8946
http://www.utsouthwestern.edu/library/

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
For a list of commands to manage subscriptions, send the command
INFO REFCARD
Reply | Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

Re: Horizontal or vertical file structure for repeated measures

Kylie Lange-3
Hi Karen,

To do multilevel/mixed effects modeling then yes, the files will need to be
in the "vertical" structure. However, I often find that I end up needing
both formats of the files - eg, vertical for the analysis, but horizontal
for some of the charts.

SPSS has the CASETOVARS command (Data> Restructure Wizard) for transforming
from one structure to the other.

Cheers,
Kylie.


-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of
Karen Harker
Sent: Monday, 16 February 2009 10:15 AM
To: [hidden email]
Subject: Horizontal or vertical file structure for repeated measures

I have inherited a set of SPSS files for several ongoing clinical trials,
some of which involve numerous follow-up assessments.  The files for each of
the assessments are in a horizontal file structure with separate sets of
variables for each of the follow-ups (i.e. dep01_f1 for follow-up 1,
dep01_f2 for follow-up #2, etc.).  This has resulted in data sets that are
fairly shallow (<100 records) but quite wide (>3000 variables).  Eventually,
the researcher will be wanting to do multilevel modeling, in addition to
time-series analysis.

I come from a database management background with only limited statistical
analysis experience.  I'm uncomfortable with the horizontal file
structure...it goes against the grain of my RDBMS training.  Furthermore,
I've read that SAS (and SPSS?) needs to have the data in vertical structure
for mixed-method analysis.  Before I propose that the data be converted to
vertical file structure, I would like to know if there are other
considerations that make the horizontal structure better?

Thanks.


Karen R. Harker, MLS
UT Southwestern Medical Library
5323 Harry Hines Blvd.
Dallas, TX  75390-9049
214-648-8946
http://www.utsouthwestern.edu/library/

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
For a list of commands to manage subscriptions, send the command
INFO REFCARD

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
For a list of commands to manage subscriptions, send the command
INFO REFCARD
Loading...