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transcript
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Introduction to Stata
Joseph D. Wolfe
January 21, 2011
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
1 The Basics
2 Data Management
3 Statistics
4 Visualization
5 Automation
6 Miscellaneous
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The Basics
A couple of quick notes.
• Stata commands are in this font
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The Basics
A couple of quick notes.
• Stata commands are in this font
• Stata commands that are show as part of the outputstart with a period (.). When you type commands, doNOT type "." before your command
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The Basics
A couple of quick notes.
• Stata commands are in this font
• Stata commands that are show as part of the outputstart with a period (.). When you type commands, doNOT type "." before your command
• I provide examples of several of the commands in thispresentation in a Stata do file that can be found at mywebsite
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Advantages of Stata
I won’t go into an elaborate comparison to other programs,but here are a several things I really appreciate about Stata:
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Advantages of Stata
I won’t go into an elaborate comparison to other programs,but here are a several things I really appreciate about Stata:
• The graphical user interface neatly displays variablesand results.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Advantages of Stata
I won’t go into an elaborate comparison to other programs,but here are a several things I really appreciate about Stata:
• The graphical user interface neatly displays variablesand results.
• Stata is well documented, and there are numeroustexts on using Stata for a variety of statistical tasks.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Advantages of Stata
I won’t go into an elaborate comparison to other programs,but here are a several things I really appreciate about Stata:
• The graphical user interface neatly displays variablesand results.
• Stata is well documented, and there are numeroustexts on using Stata for a variety of statistical tasks.
• StataCorp works hard to ensure backward compatibility.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Advantages of Stata
I won’t go into an elaborate comparison to other programs,but here are a several things I really appreciate about Stata:
• The graphical user interface neatly displays variablesand results.
• Stata is well documented, and there are numeroustexts on using Stata for a variety of statistical tasks.
• StataCorp works hard to ensure backward compatibility.
• Stata has lots of tools to facilitate work flow andreplication.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Getting Help
There are 3 general ways of getting help with Stata:
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Getting Help
There are 3 general ways of getting help with Stata:
1 Stata’s help command
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Getting Help
There are 3 general ways of getting help with Stata:
1 Stata’s help command
2 The Stata manual - PDF documentation can beaccessed from the Help pull down menu or at thebottom of a command’s help file.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Getting Help
There are 3 general ways of getting help with Stata:
1 Stata’s help command
2 The Stata manual - PDF documentation can beaccessed from the Help pull down menu or at thebottom of a command’s help file.
3 StataList
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The Graphical User Interface
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The Graphical User Interface
1 Results Window: Displays results from commands,error messages, etc.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The Graphical User Interface
1 Results Window: Displays results from commands,error messages, etc.
2 Command Window: Allows us to work interactively withStata.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The Graphical User Interface
1 Results Window: Displays results from commands,error messages, etc.
2 Command Window: Allows us to work interactively withStata.
3 Variable Window: Displays the variables in a dataset.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The Graphical User Interface
1 Results Window: Displays results from commands,error messages, etc.
2 Command Window: Allows us to work interactively withStata.
3 Variable Window: Displays the variables in a dataset.
4 Review Window: Displays the previous commands thathave been used.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Speaking Stata
Stata has its own language. We have to write commands ina specific format for Stata to understand what we want. Thisis referred to as syntax. The basic language syntax is:
[prefix :] command [varlist ] [=exp] [if ] [in] [weight ][using filename] [, options]
You can find the syntax for specific commands by typinghelp and the command in the command window.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The Command Window
Now that we have an idea how Stata works, let’s jump rightin and look at how to use the command window.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The Command Window
Now that we have an idea how Stata works, let’s jump rightin and look at how to use the command window.
For example, the display command is great for quickcalculations used in the command window.
. di 2 + 24
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The Command Window
Now that we have an idea how Stata works, let’s jump rightin and look at how to use the command window.
For example, the display command is great for quickcalculations used in the command window.
. di 2 + 24
You could probably do all your work using the commandwindow, but in the next section we’ll talk about why that’s nota good strategy for conducting serious research.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Data Management
Several of the issues I mention about data management canbe found in Scott Long’s Workflow book. You should gothere for more detailed information on this topic.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Setting Your Directories
A directory is where Stata looks for and saves information.So, if you want to use a dataset in a specific folder, you haveto Stata to look in that folder. Let’s check where my directlyis currently set by using the pwd command.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Setting Your Directories
A directory is where Stata looks for and saves information.So, if you want to use a dataset in a specific folder, you haveto Stata to look in that folder. Let’s check where my directlyis currently set by using the pwd command.
. pwd/Users/jdwolfe/Documents/
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Setting Your Directories
A directory is where Stata looks for and saves information.So, if you want to use a dataset in a specific folder, you haveto Stata to look in that folder. Let’s check where my directlyis currently set by using the pwd command.
. pwd/Users/jdwolfe/Documents/
If I wanted to work on a project I’m involved with, I wouldneed to change the directory by using the cd command.
. cd "/Users/jdwolfe/Documents/Project"/Users/jdwolfe/Documents/Project
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Importing and Exporting Data
Let’s get some data! To start off, let’s just use data that isshipped with Stata.
. sysuse auto(1978 Automobile Data)
The sysuse command is a quick way to load data includedwith Stata ( sysuse dir will list other available data).However, you’ll need a different command to load data inone of your personal folders. Let’s save this dataset in anew folder and then reload it.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Importing and Exporting Data
We’ve set our directory, so all we need is the savecommand.
. save auto2file auto2.dta saved
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Importing and Exporting Data
We’ve set our directory, so all we need is the savecommand.
. save auto2file auto2.dta saved
To make sure I’ve saved it correctly, I can check thecontents of the directory.
. dir<dir> 8/26/10 16:33 .<dir> 8/26/10 16:33 ..5.8k 8/26/10 16:33 auto2. dta
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Importing and Exporting Data
Now, because the data is in my folder, I need the usecommand.
. use auto2.dta, clear(1978 Automobile Data)
For other data formats, see outsheet, insheet, outfile, andinfile.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log Files
Although the point-and-click option is enticing, it inhibitsreplication of results. Using do-files allows you to have acopy of your work that you can always come back to andreuse in other projects.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log Files
Although the point-and-click option is enticing, it inhibitsreplication of results. Using do-files allows you to have acopy of your work that you can always come back to andreuse in other projects.
• To open a do-file click the Stata do-file editor icon in thetoolbar (in Stata 11, it’s the 7th icon to the right).
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log Files
Although the point-and-click option is enticing, it inhibitsreplication of results. Using do-files allows you to have acopy of your work that you can always come back to andreuse in other projects.
• To open a do-file click the Stata do-file editor icon in thetoolbar (in Stata 11, it’s the 7th icon to the right).
• Notice that the do-file has it’s own toolbar. Use this tosave, open, print, and run files.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log Files
Although the point-and-click option is enticing, it inhibitsreplication of results. Using do-files allows you to have acopy of your work that you can always come back to andreuse in other projects.
• To open a do-file click the Stata do-file editor icon in thetoolbar (in Stata 11, it’s the 7th icon to the right).
• Notice that the do-file has it’s own toolbar. Use this tosave, open, print, and run files.
• You may want to use a text editor with more options.Here are several to check out. For PCs, there isUltraedit and Notepad++ (free!). I have a Mac so I useTextWrangler, a stripped-down version of BBEdit. It’sfree and scriptable!
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log Files
I usually keep a do-file template on hand. When I want anew do file, I open my template and then save it with a newname. Here’s an example (this template can be downloadedfrom my website):
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log Files
1> capture log close2> log using NAMEOFDOFILE, replace text3>4> // program: NAMEOFDOFILE5> // task:6> // project:7> // author:8>9> version 11
10> clear all11> macro drop _all12> set linesize 8013> set more off14>15> // #116> // Describe step17>18> log close19> exit
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log FilesLet’s decode some of this.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log FilesLet’s decode some of this.
1 Lines 1-2: I begin by closing previous logs and creatinga new one. We’ll talk about this more in a second
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log FilesLet’s decode some of this.
1 Lines 1-2: I begin by closing previous logs and creatinga new one. We’ll talk about this more in a second
2 Lines 4-7: I put some basic information about the do-fileand what it is doing. You can add notes to a do file byusing "//", "*", or surrounding text with "/*" and "*\"
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log FilesLet’s decode some of this.
1 Lines 1-2: I begin by closing previous logs and creatinga new one. We’ll talk about this more in a second
2 Lines 4-7: I put some basic information about the do-fileand what it is doing. You can add notes to a do file byusing "//", "*", or surrounding text with "/*" and "*\"
3 Line 9: Version control is incredibly important.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log FilesLet’s decode some of this.
1 Lines 1-2: I begin by closing previous logs and creatinga new one. We’ll talk about this more in a second
2 Lines 4-7: I put some basic information about the do-fileand what it is doing. You can add notes to a do file byusing "//", "*", or surrounding text with "/*" and "*\"
3 Line 9: Version control is incredibly important.
4 Lines 10-11: I clear all information from any previoussessions that may still be in memory
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log FilesLet’s decode some of this.
1 Lines 1-2: I begin by closing previous logs and creatinga new one. We’ll talk about this more in a second
2 Lines 4-7: I put some basic information about the do-fileand what it is doing. You can add notes to a do file byusing "//", "*", or surrounding text with "/*" and "*\"
3 Line 9: Version control is incredibly important.
4 Lines 10-11: I clear all information from any previoussessions that may still be in memory
5 Lines 12-13: I set the linesize and set more off. Withoutset more off , Stata will pause while running the dofile.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log FilesLet’s decode some of this.
1 Lines 1-2: I begin by closing previous logs and creatinga new one. We’ll talk about this more in a second
2 Lines 4-7: I put some basic information about the do-fileand what it is doing. You can add notes to a do file byusing "//", "*", or surrounding text with "/*" and "*\"
3 Line 9: Version control is incredibly important.
4 Lines 10-11: I clear all information from any previoussessions that may still be in memory
5 Lines 12-13: I set the linesize and set more off. Withoutset more off , Stata will pause while running the dofile.
6 Lines 15-17: I do my work in steps #1 through how evermany I need.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Do and Log FilesLet’s decode some of this.
1 Lines 1-2: I begin by closing previous logs and creatinga new one. We’ll talk about this more in a second
2 Lines 4-7: I put some basic information about the do-fileand what it is doing. You can add notes to a do file byusing "//", "*", or surrounding text with "/*" and "*\"
3 Line 9: Version control is incredibly important.
4 Lines 10-11: I clear all information from any previoussessions that may still be in memory
5 Lines 12-13: I set the linesize and set more off. Withoutset more off , Stata will pause while running the dofile.
6 Lines 15-17: I do my work in steps #1 through how evermany I need.
7 Lines 18-19: Finally, I close the log and exit.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Log Files
While do-files hold commands, log files record both thecommands used and the output created during a session.Look back at the template to see where I use thecommands I describe below.
• I always begin with capture log close . Thismakes sure that I’m not writing information into adifferent log file that may have been accidentally leftopen.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Log Files
While do-files hold commands, log files record both thecommands used and the output created during a session.Look back at the template to see where I use thecommands I describe below.
• I always begin with capture log close . Thismakes sure that I’m not writing information into adifferent log file that may have been accidentally leftopen.
• log using FILENAME, replace text . Thiscreates a log or replaces an old logs of the same name,and text saves it as a text file
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Log Files
While do-files hold commands, log files record both thecommands used and the output created during a session.Look back at the template to see where I use thecommands I describe below.
• I always begin with capture log close . Thismakes sure that I’m not writing information into adifferent log file that may have been accidentally leftopen.
• log using FILENAME, replace text . Thiscreates a log or replaces an old logs of the same name,and text saves it as a text file
• At the end of do-files, I also include the commandclose log . Otherwise, the log will continue recordinganything that Stata does.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Variables
I spend a large chunk of my time on projects creating andrecoding variables. Here are some commands I’ve foundindispensable in creating and changing variables. See step#3 for an example using these commands.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Variables
I spend a large chunk of my time on projects creating andrecoding variables. Here are some commands I’ve foundindispensable in creating and changing variables. See step#3 for an example using these commands.
• generate - creates new variables
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Variables
I spend a large chunk of my time on projects creating andrecoding variables. Here are some commands I’ve foundindispensable in creating and changing variables. See step#3 for an example using these commands.
• generate - creates new variables
• recode - recodes an existing variable
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Variables
I spend a large chunk of my time on projects creating andrecoding variables. Here are some commands I’ve foundindispensable in creating and changing variables. See step#3 for an example using these commands.
• generate - creates new variables
• recode - recodes an existing variable
• replace - replaces the contents of an existing varable
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Variables
I spend a large chunk of my time on projects creating andrecoding variables. Here are some commands I’ve foundindispensable in creating and changing variables. See step#3 for an example using these commands.
• generate - creates new variables
• recode - recodes an existing variable
• replace - replaces the contents of an existing varable
• egen - like gen but has lots of extensions
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Variables
There are also several commands that should usually beincluded when creating or revising a variable.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Variables
There are also several commands that should usually beincluded when creating or revising a variable.
• label variable - adds or changes the label for a variable
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Variables
There are also several commands that should usually beincluded when creating or revising a variable.
• label variable - adds or changes the label for a variable
• label define and label value - use these commands toadd labels to the categories of a variable
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Variables
There are also several commands that should usually beincluded when creating or revising a variable.
• label variable - adds or changes the label for a variable
• label define and label value - use these commands toadd labels to the categories of a variable
• notes - add notes to data and variables. I usually add anote telling me the name of the do file used to create avariable. This very helpful when, weeks or months later,I need to see exactly how I created a variable.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Statistics
Stata can do a wide range of statistical analyses. We don’thave time to cover them all, or explain what they do in detail.In the next few slides, I list some of the more basiccommands. If you want more information on a command orusing a statistical technique in Stata, click on the commandname of the statistic or check out Stata’s bookstore.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Descriptive Statistics
Stata has lots of commands for getting basic statistics aboutyour data.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Descriptive Statistics
Stata has lots of commands for getting basic statistics aboutyour data.
• list - lists values of variables for observations
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Descriptive Statistics
Stata has lots of commands for getting basic statistics aboutyour data.
• list - lists values of variables for observations
• codebook - nice table of basic descriptive statistics(with compact option) or more detailed informationabout variables
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Descriptive Statistics
Stata has lots of commands for getting basic statistics aboutyour data.
• list - lists values of variables for observations
• codebook - nice table of basic descriptive statistics(with compact option) or more detailed informationabout variables
• summarize - also provides nice table of basicdescriptive statistics or more detailed information aboutvariable with detail option
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Descriptive Statistics
Stata has lots of commands for getting basic statistics aboutyour data.
• list - lists values of variables for observations
• codebook - nice table of basic descriptive statistics(with compact option) or more detailed informationabout variables
• summarize - also provides nice table of basicdescriptive statistics or more detailed information aboutvariable with detail option
• tabulate - get a table of frequencies or, if you specifytwo variables, a two-way table of frequencies
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Test and RegressionCommands
Here’s a short list of some basic test and regressioncommands.
• ttest - Mean comparison tests
• regress - Linear regression for continuous outcomes
• logit - Logistic regression for binary outcomes
• mlogit - Multinomial logistic regression for categoricaloutcomes
• poisson - Poisson regression for count outcomes
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
More Advanced Models
Here are a few of Stata’s more specialized statisticalcapabilities.
• xt - These commands are intended for cross-sectionalpanels and longitudinal data.
• svy - These commands make adjustments for complexsurvey designs.
• st - These commands deal with survival-time data.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Tables
For a quick and dirty table, you can copy results from Stata’sresults window and paste them into a word processor. If youuse a fixed font, e.g., courier new, it will look exactly like itdid in Stata’s Result window.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Tables
For a quick and dirty table, you can copy results from Stata’sresults window and paste them into a word processor. If youuse a fixed font, e.g., courier new, it will look exactly like itdid in Stata’s Result window.
For publication-quality tables, try esttab. This is a userwritten program. You’ll have to download it. For instructions,see the Miscellaneous section of the presentation.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Graphs
Stata’s graphs can be great but can also get verycomplicated. Although there are pull down menus that willhelp create graphs, I strongy recommend using a saveddo-file. This way can reproduce your graphs and reuse thecommands. I provide a few simple examples, but like theother topics we’ve discussed, there are lots of options thatcan be added to get what you want.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
GraphsHistograms are an quick way to check variable frequencies.The basic command is straightforward:
. histogram price, freq
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
GraphsFor two variables, you want to use the a twoway plot. Here’san example:
. graph twoway scatter price length
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Graphs
For more than two variables, you’ll want a matrix graph.
. graph matrix price mpg length
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Graphs
To save graphs, use the graph export command. Forexample, we could save the matrix graph we just created:
. graph export grmatrix.png, replace
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
LocalsLocals allow you to designate letters or a word to representother text, variables, or numbers.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
LocalsLocals allow you to designate letters or a word to representother text, variables, or numbers.
For example, I create a local at the beginning of my do-filesthat contains the name of the do-file.
. local pgm "stintro01"
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
LocalsLocals allow you to designate letters or a word to representother text, variables, or numbers.
For example, I create a local at the beginning of my do-filesthat contains the name of the do-file.
. local pgm "stintro01"
Then, I can use that local to add notes, captions to graphs,etc. For example, to add the name of the do file to a variablenote, I would say:
. note price: ` pgm’
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
LocalsLocals allow you to designate letters or a word to representother text, variables, or numbers.
For example, I create a local at the beginning of my do-filesthat contains the name of the do-file.
. local pgm "stintro01"
Then, I can use that local to add notes, captions to graphs,etc. For example, to add the name of the do file to a variablenote, I would say:
. note price: ` pgm’
You’ll notice quotes around the local when I use it in acommand. The quote on the left is called a grave accent,which is located at the top left of your keyboard next to thenumber 1. On the right, there is a single quote (A.K.A., anapostrophe).
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Loops
Loops allow you to do a command or a series of commandsover and over without having to type it all out. This is can bea lifesaver!!
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Loops
Loops allow you to do a command or a series of commandsover and over without having to type it all out. This is can bea lifesaver!!
Pretend that we just created the variables make, price, mpg,rep78, and headroom in the auto dataset. Now, we want toattach a note that includes the the name of the do-fle.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Loops
Loops allow you to do a command or a series of commandsover and over without having to type it all out. This is can bea lifesaver!!
Pretend that we just created the variables make, price, mpg,rep78, and headroom in the auto dataset. Now, we want toattach a note that includes the the name of the do-fle.
Well, we could go through every variable like this:
. note make: ` pgm’
. note price: ` pgm’
. note mpg: ` pgm’
. note rep78: ` pgm’
. note headroom: ` pgm’
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Loops
The foreach command can do this much faster.
. foreach var in make price mpg rep78headroom {2. note ` var’: ` pgm’3. }
This was a short example, so maybe the foreachcommand doesn’t make a lot of sense. However, if youneed to tabulate 20 variables or recode the missing in 200variables, the foreach command can save you a lot oftime.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
The forvalues command is similar except that it loopsover consecutive values.
. forvalues x = 5/10 {2. sum price if trunk==`x’3. }
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
User-Written Software
For specialized tasks, you may need user-written software.To find the software, use the findit comand. For example,to find the esttab package type
findit esttab
Scroll down until you find the right package and click the linkto download.
If you are using a computer that will not allow you to changefiles, you’ll need to type:
sysdir set PLUS "PATHTOFOLDER"
Then try downloading again. The program should bedownloaded to the chosen folder.
Introduction toStata
Joseph D.Wolfe
Outline
The Basics
DataManagement
Statistics
Visualization
Automation
Miscellaneous
Websites
Here are a list of websites that may be of interest.
• Stata’s Website
• The Stata Journal
• Stata TutorialsUCLA Statistical Computing
• General Introduction to StataGermán Rodríguez, Princeton University
• A SAS User’s Guide to StataDan Blanchette, Duke University