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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.
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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)
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
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
Nested/master do files Flexible terminology Setting types of data Interactive help Switch output (log file) on/off Copy and paste Advantages and disadvantages of Stata
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 APPEND Data 1 Data 2 Data 1 Data 2
_merge values Data 1 (indi) ‘master’ 1 Data 2 (indj) ‘using’ 3 2