Software for data management: The contribution of Stata Dr Karen Robson, Senior Research Fellow, The Geary Institute, University College Dublin, Ireland

Getting acquainted with Stata StataCorp develops and distributes Stata, software for statistical analysis. Stata is available for Windows, Macintosh, and Unix computers. Stata is used by medical researchers, biostatisticians, epidemiologists, economists, sociologists, political scientists, geographers, psychologists, social scientists, and other research professionals needing to analyze data. Gaining popularity in the social and medical sciences Particularly useful for handling large-scale longitudinal data

Stata SE (for large data sets) can analyze datasets with as many as 32,766 variables, and the only limit on observations is the amount of RAM on your computer can handle string variables with a maximum length of 244 characters can handle matrices up to 11,000 x 11,000. requires at least 512 megabytes of RAM and 80 megabytes of disk space

Stata/Intercooled (the standard one) can analyze datasets with as many as 2,047 variables, and the only limit on observations is the amount of RAM on your computer can handle string variables with a maximum length of 244 characters can handle matrices up to 800 x 800.

Small Stata A smaller, student version of Stata (for educational purchases only)

Stata MP The fastest version of Stata (for dual-core and multicore/multiprocessor computers) Stata/MP is the fastest and largest version of Stata.

Resources StataCorp website (www.stata.com)

Resources StataCorp website (www.stata.com) Timberlake website (www.timberlake.co.uk)

Resources StataCorp website (www.stata.com) Timberlake website (www.timberlake.co.uk) UCLA Stata “portal” (http://www.ats.ucla.edu/stat/)

Resources StataCorp website (www.stata.com) Timberlake website (www.timberlake.co.uk) UCLA Stata “portal” (statcomp.ats.ucla.edu/stata) Statalist (www.hsph.harvard.edu/statalist)

Resources StataCorp website (www.stata.com) Timberlake website (www.timberlake.co.uk) UCLA Stata “portal” (statcomp.ats.ucla.edu/stata) Statalist (www.hsph.harvard.edu/statalist) Stata Journal (www.stata-journal.com)

As well, available Dec 2008

Launching Stata OS contingent Default window preferences Window preferences fully adjustable Auto memory set

Comparing with SPSS Start up differences

Comparing with SPSS Start up differences With data file open

Comparing with SPSS Start up differences With data file open Viewing data data viewer, data editor

Comparing with SPSS Start up differences With data file open Viewing data data viewer, data editor Viewing variables

Comparing with SPSS Start up differences With data file open Viewing data data viewer, data editor Viewing variables Viewing output/commands output window buffer, log files

Comparing with SPSS Start up differences With data file open Viewing data data viewer, data editor Viewing variables Viewing output/commands output window buffer, log files Syntax and “do files”

Variable window INPUT Stata command window Do file Pull-down menu Review window Computation RESULTS Output window Log file

Advantages and disadvantages of Stata User driven Free STBs Dedicated journal Web active Memory requirements Backward compatible Change! SPSS dominance Orientated to writing syntax/code Pull-down windows debate! Now in version 8 forward

Advantages and disadvantages of Stata Easier code Easier data handling Clarity of operations/ feedback Results table function Before version 8, limited graphics Now, complex graphics Variable labelling Editing of output

Advantages and disadvantages of Stata Copy and paste Nested/master do files Flexible terminology Setting types of data Interactive help Switch output (log file) on/off

Overview of analytic techniques Too numerous to mention! Comprehensive manuals A selection: All types of regression Survey package Epidemiological package Multilevel modelling Time series functions Cluster analysis

Data Data files .dta Stat/Transfer software

Stata – using wide and long file formats Wide file formats (everything you add goes to the right of the existing data) Long file formats (everything you add goes underneath the existing data)

MERGE Data 1 Data 2 APPEND

Data 1 (indi) ‘master’ Data 2 (indj) ‘using’ _merge values 1 3 2