Research Catalog

Title

Longitudinal data and SAS : a programmer's guide / Ron Cody.

Author

Cody, Ronald P.

Publication

Cary, N.C. : SAS Institute, 2001.

Items in the Library & Off-site

Holdings

Details

Description

xx, 174 pages : illustrations; 23 cm

Subjects

• Statistics
• Longitudinal method
• Méthode longitudinale
• Statistique
• SAS (Computer file)
• SAS (Logiciel)

Note

• Includes index.

Contents

List of Programs -- Preface -- Acknowledgments -- 1. The RETAIN Statement -- Introduction -- Demonstrating a DATA Step with and without a RETAIN Statement -- Generating Sequential SUBJECT Numbers Using a Retained Variable -- Using a SUM Statement to Create SUBJECT Numbers -- Demonstrating That Variables Read with a SET Statement Are Retained -- A Caution When Using a RETAIN Statement -- 2. The LAG and DIF Functions -- Introduction -- Using the LAG Function to Compute Differences -- Demonstrating Some Related Functions: LAG2, LAG3, and So Forth -- Demonstrating the DIF Function -- 3. FIRST. and LAST. Temporary Variables -- Introduction -- How to Create FIRST. and LAST. Temporary Variables -- Using More Than One BY Variable -- A Simple Application Using FIRST. and LAST. Variables -- 4. Flags and Counters -- Introduction -- Using a Flag Variable to Determine If a Particular Event Ever Occurred in Any One of Several Observations for Each Subject -- Counting the Number of Positive Outcomes for Each Patient -- 5. Summarizing Data Using PROC MEANS and PROC FREQ -- Introduction -- Using PROC MEANS to Output Means to a Data Set -- Comparing CLASS and BY Statements with PROC MEANS -- Computing Other Descriptive Statistics -- Automatically Naming the Variables in the Output Data Set -- Demonstrating an Alternative Way to Select Specific Descriptive Statistics for Selected Variables -- Adding Additional Variables to the Summary Data Set Using an ID Statement -- Specifying More Than One CLASS Variable -- Selecting Multi-Way Breakdowns Using the TYPES Statement -- Using the PROC MEANS CHARTYPE Option to Simplify the _TYPE_ Interpretation -- Comparing PROC MEANS and PROC FREQ for Creating an Output Data Set Containing Counts -- Counting Frequencies for a Two-Way Table -- 6. Using PROC SQL with Longitudinal Data -- Introduction -- Creating a Demonstration Data Set -- A Simple SQL Query -- Using PROC SQL to Count Observations within a BY Group -- Demonstrating a HAVING Clause -- Using PROC SQL to Create a Macro Variable -- Using a Summary Function to Compute Group Means -- 7. Restructuring SAS Data Sets Using Arrays -- Introduction -- Creating a New Data Set with Several Observations per Subject from a Data Set with One Observation per Subject -- Another Example of Creating Multiple Observations from a Single Observation -- Going from One Observation per Subject to Many Observations per Subject Using Multidimensional Arrays -- Demonstrating the Use of a Multidimensional Array -- An Alternative Program -- Another Example of a Multidimensional Array -- 8. Restructuring SAS Data Sets Using PROC TRANSPOSE -- Introduction -- Going from One Observation to Several Observations -- Another Example of Creating Multiple Observations from a Single Observation -- Going from One Observation per Subject to Many Observations per Subject -- Creating a Data Set with One Observation per Subject from a Data Set with Multiple Observations per Subject -- 9. Study One: Operations on a Clinical Database -- Introduction -- Description of the Clinical Data Set -- Selecting the First or Last Visit for Each Patient -- Computing Differences between the First and Last Visits -- Another Method of Computing Differences between the First and Last Visits -- Computing Differences between Every Visit -- Counting the Number of Visits for Each Patient (DATA Step Approach) -- Counting the Number of Visits for Each Patient (PROC FREQ) -- Counting the Number of Visits for Each Patient (PROC MEANS) -- Counting the Number of Visits for Each Patient (PROC SQL) -- Selecting All Patients with n Visits (DATA Step Approach) -- Selecting All Patients with n Visits (PROC FREQ Approach) -- Selecting All Patients with Two Visits (Using PROC SQL) -- Selecting All Patients with Two Visits (Using SQL in One Step) -- Using PROC SQL to Create a Macro Variable -- Computing Summary Statistics for Each Patient (Using PROC MEANS) -- Computing Summary Statistics for Each Patient (Using PROC SQL) -- Adding a Value from the First Visit to Each Subsequent Visit -- Looking Ahead: Making a Decision about the Current Observation Based on Information in the Next Observation -- Using Flags to Ascertain Vitamin Use -- Using PROC FREQ to Ascertain Vitamin Use -- Counting the Number of Routine Visits for Each Patient -- 10. Study Two: Operations on Daily Weather Data and Ozone Levels -- Introduction -- The OZONE Data Set -- Computing Weekly Averages -- Using the MOD Function to Group Data Values -- Computing a Moving Average for a Single Variable -- 11. Study Three: Producing Summary Reports on a Library Data Set -- Introduction -- Computing the Number of Books per Patron Visit and by Library -- Computing the Number of Patrons by Day of Week and Library -- Generating a Table of LC Categories by Age Group and Overall -- 12. Useful Macros -- Introduction -- Listing All or Part of a Data Set -- Computing Differences between Successive Observations -- Computing Differences between the First and Last Observations per Subject -- Computing a Moving Average -- Computing Cell Means and Counts -- Counting the Number of Observations per Subject -- Appendix. List of Data Files and SAS Data Sets -- The TEST_SCORES Data Set -- The CLINICAL Data Set -- The CLIN_FIRST Data Set -- The OZONE Data Set -- The LIBRARY Data Set -- Index.

ISBN

• 1580259243
• 9781580259248

LCCN

2002510600

Owning Institutions

Columbia University Libraries