stata mini course fall 2015 jane leber herr [email protected] littauer 113 1stata mini course...
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STATA Mini Course
Fall 2015
Jane Leber Herr
Littauer 113
Stata Mini Course – Spring 2015
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Goal: Make you comfortable with Stata
1) Can’t teach you all of Stata
2) But can teach you basics AND
3) Teach you how to teach yourself Stata
The Stata Mini-Course
Stata Mini Course – Spring 2015
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Why is Stata so AWESOME? Let me count the ways…
1) In Excel, you can’t produce a step-by-step record.In Stata, .do files do exactly that!
Why is that important?
• Can remind yourself what you did (and why)
• Can tweak one thing, and rerun – Ta Da!
• Can easily find bugs in your code
Why use Stata??
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Why is Stata so AWESOME? Let me count the ways…
1) In Excel, you can’t produce a step-by-step recordIn Stata, .do files do exactly that!
2) Excel is MUCH slower at manipulating data
3) Stata produces much nicer graphs
4) Excel can’t handle econometrics the way Stata can!
How much data manipulation ok in Excel?
NONE!
Why Stata??
Stata Mini Course – Spring 2015
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1) Stata mini-course lectures & problem sets
Class Dates:
• Tuesday 2/24
• Tuesday 3/10
• Tuesday 3/31
Problem Set Dates:
• Friday 2/20
• Friday 3/6
• Friday 3/27
• Friday 4/10
Stata Course Structure
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2) Stata office hours (see isite)
Stata Course Structure
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3) Help by email
We will try to respond to emails ASAP, but goal:
• Within 24 hours during the week
• By Monday if over the weekend
Google your question!
Email etiquette:
• If you email both of us, do it in a way that we can tell (then we can cc: each other/not duplicate effort)
• If you figure out the answer on your own, let us know!
Stata Course Structure
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Resources available on the isite:
• Class schedule and pset due dates
• Announcements (e.g., OH switches)
• Our contact info
• OH schedule (appointment sign up)
• Lecture materials
• Problem Sets
• Other AWESOME resources
Stata iSite
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Download from HUIT (see details in PSet #1)
• Keyserver Client (IMPORTANT!)
• Stata (tips on how to figure out which version you need)
• Harvard VPN
Help?
• Email HUIT ([email protected])
• Science Center Computer lab
Downloading Stata
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Stata Windows:
• Command line
• Results panel
• Variables
• List of commands you’ve run so far
What is Stata?
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Most awesome part of Stata!– File that holds all the commands you want Stata to run
– Can be a file that:
• Builds your dataset & variables
• Runs all your regressions
• Builds your results tables
• Builds your figures
• Or any combination!
– You will build a .do file for each Stata pset
.do files!
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Where is the .do file? – .do file button
– Window: “do file editor”
.do file example
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Saving the results in a .log file – log using example.log
…log close
– For Stata psets, will send your instructor:
• your .do file
• the .log file it creates that holds all the results
.log file
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1) Comment at top (e.g., purpose of the .do file)
• Comments:*/* */
2) Save the .do file:
• .do files do NOT autosave – SAVE FREQUENTLY!
Let’s build a .do file…
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3) Change the working directory (folder):
• Easiest if working in the directory where the data live
• Current directory shown at bottom left
• Short-cut Tip #1:
– Change directory in “File/Change Working Directory”
– Can now see path name in Results window
– Copy that line of code into the .do file you are building
Let’s build a .do file…
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4) Start a .log file
• log using Stata_Lect1.log
Let’s build a .do file…
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Aside: How tell Stata run command from .do file??
1) Choose File/“do”: Will run the WHOLE .do file
2) Choose “execute” button from .do file:
• If nothing highlighted: will run whole .do file
• If lines highlighted: will run JUST those lines
3) Highlight (partial) line:
• If PC: control D
• If mac: control shift D
Let’s build a .do file…
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5) Open a dataset
• use StataClass_Raw
6) Let’s look at the data!
• browse
Let’s build a .do file…
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5) Open a dataset
• use StataClass_Raw
6) Let’s look at the data!
• browse
• describe
• summarize
Let’s build a .do file…
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Figuring out how a command works:
• Link to even MORE help!
• Command syntax: summarize [varlist], …options
• List of options
• Descriptions
• EXAMPLES!
• If don’t know command name:
– “search blah”
– Google it!
Stata help files
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5) Open a dataset
• use StataClass_Raw
6) Let’s look at the data!
• browse
• describe
• summarizesummarize uhrswork, detail
Let’s build a .do file…
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5) Open a dataset
• use StataClass_Raw
6) Let’s look at the data!
• browse
• describe
• summarizesummarize uhrswork, detail
• tabulate nchild if age>=20 & age<=30tabulate nchild, nolabel
Let’s build a .do file…
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7) Build variable “female”:
• tab sex
• generate female = 1 if sex==“female”
• tab sex, nolabel
• generate female = 1 if sex==2
• browse the data (browse sex female)
• notice “missing values” for the men(no values for them if “tab female”)
• replace female = 0 if sex==1(redo “tab female”)
Lets build a variable!
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8) Cut data down to size:
• Drop the men
• Keep if age>=30 & age<=40
9) Save updated dataset:
• Do NOT call by same name as before!
• save StataClass_Lect1
Rerun from the start…
Saving Data
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10) Explore hours worked by # of kids:• sum uhrswork if nchild==0
sum uhrswork if nchild>0
• bysort nchild: sum uhrswork
11)Close the .log file
Rerun from the start…
Exploring Hrs Worked by #Kids
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ASIDE: Capitalization matters!
• Commands: Summarize ≠summarize
• Variable names: Age ≠age
Useful things to know…
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Useful things you learn:
1) Other ways to build variables(e.g., using tabulate)
2) Labeling variables
3) Other useful commands
4) Lots of other tips that will be invaluable for doing the psets
Other things shown in the “clean” .do file:
Stata Mini Course – Spring 2015