Module Introduction and Getting Started with Stata

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Session 1

• Module Introduction and Getting Started with Stata

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Introduction

• Welcome
• Housekeeping
• Introductions
• Name, job, district, team

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Module Overview

• Module objectives are to provide you with
• Skills in data analysis
• Keeping in mind the analysis objectives
• While learning the use of a specialised
  statistical software package Stata
• There will be a strong emphasis on conducting
• meaningful analyses and on the interpretation
• of the results.

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Module content

• Data management
• Data entry principles and practices
• using Epi Info
• designing data capture screens,
• labelling and entering data, etc.
• Simple statistical analysis
• in Epi Info
• and using the statistics package, Instat.
• Report writing.

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Duration and timetable
Morning Afternoon
Day 1 Getting started with Stata Continued
Day 2 Tables Project work part 1
Day 3 Graphs Project work part 2
Day 4 Reviewing inference estimation and confidence intervals Reviewing inference Hypothesis testing
Day 5 Tests of association in 2-way tables Sampling weights
Day 6 Project work part 3 writing the report Putting it all in context
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Module Learning Objectives

• At the end of the module, participants will
• appreciate the power of Stata as a statistical
  package
• be able to undertake elementary data management
  and statistical analyses in Stata
• have updated their practical knowledge of the key
  statistical inference concepts of estimation and
  hypothesis testing
• be able to produce graphs and tables using Stata,
  
• have sufficient knowledge of Stata to be able to
  work independently to produce other analyses

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Prerequisites

• Completion of Modules 1 and 2
• At least a theoretical knowledge of statistical
  inference

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Resources

• Stata software - version 10
• This should be installed already
• It may need updating and a Stata package adding
  see later slides
• Guide to survey data analysis using Stata
• Part 1 (Chapters 1 to 10) is used here
• Part 2 (Chapters 11 to 20) is supplied for
  reference
• Inference guide
• Used particularly in Sessions 7 and 8

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Concepts more than software

• The emphasis is on the concepts of data analysis
  and statistical inference
• Using Stata
• Rather than just on Stata itself
• Here we largely use the menus and dialogues
• Though ways of using and reading commands are
  introduced
• Software is now easy to master
• It is the statistical concepts that benefit from
  a course

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Learning objectives sessions 1 and 2

• These two sessions are about Stata
• Participants will be able to
• Load and save data
• Explore data
• Using describe, codebook, summarize, etc
• Calculate new variables
• Using generate, recode, etc
• Add labels to variables and to levels of a factor
• Create subsets of data using drop and keep

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Session Contents

• In this session we look in particular at
• Windows and menus in Stata
• Opening Stata data files
• Stata dialogues
• Typing and editing commands
• Using Stata as a calculator
• Exiting Stata

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The four Stata windows
Review Stata Results Variables and window for
typing Stata commands
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The Stata menus and toolbar

• The three most important menus
• Data (for organising and managing the data),
• Graphics (for visual exploration presentation),
• Statistics (for analysis).

Data, Graphics, Statistics
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Check Stata is up-to-date

• Use Help gt Official updates

If updating is needed, either Do it
automatically if you are connected to the
internet Or use the files on the CD/DVD that are
under Stata resources
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The Data and Graphics Menus
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Your turn

• Click on several menus and explain theirusage to
  your neighbour
• You can deduce the menu from the logic of the
  task
• e.g. to draw a graph you go to the graphics
  menu!
• Which menu would you probably need to use to
• save data?
• sort a data set?
• produce a bar chart?
• tabulate the data?
• Check by finding the dialogue in Stata

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Stata guide Section 1.2

• You use Stata as a calculator
• Go through this section together
• Check the buttons at the bottom of the dialogue
• They are the same on all dialogues

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Using Stata as a calculator

• To perform calculations, use
• Data ? Other utilities ? Hand calculator

Type 23 into the Expression slot
Press the Submit button
See answer in Results Window, and appearance of
corresponding command in both the Results and
Review windows.
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Results from the dialogue

• You can get back to any dialogue box by typing db
  in front of the command name.
• e.g. db display

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Creating an expression
Click create and then complete the resulting
expression builder dialogue box. Or type display
ln(10)
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Stata guide Section 1.3

• From this point you use a dataset that is
  supplied
• Check that you have a working directory
• And that it has the files for this module
• Copy them in, if not
• They are on the CD/DVD under Stata resources
• You could install the Stata package as well if
  you wish.
• Then use Files gt Change working directory
• To set this directory for the future

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Opening a Stata data file

• Use the menu sequence
• File, Open
• select (highlight) the file named
• K_combined_short.dta
• and click on Open
• This will load the data from the Kenya
  socio-economic survey into Stata
• Look at the Variables Window. What do you
  observe?

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Options within the Data menu
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An example of a dialogue box
Dialogue results from using the menu sequence
Data, ? Describe data, ? Describe data
contents (codebook)
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In the codebook dialogue box

• The Submit button
• instructs Stata to execute the command, leaving
  the dialogue box visible.
• The OK button does the same,
• but closes the dialogue box.
• Cancel closes the dialogue box
• without submitting the command to Stata.
• The R button resets the dialogue box
• to its empty form.
• ? gives help on the command
• associated with the dialogue box.
• The word codebook at the top of the dialogue
• shows codebook is the command that will be
  generated

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Another dialogue box
Dialogue results from using the menu sequence
Data, Describe data, Summary statistics
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Results from codebook and summarize


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Your turn

• In Chapter 1 of the Stata guide, go through
• Section 1.3
• Section 1.4
• Section 1.5
• Ask a resource person if you are unclear about
• any parts of the above sections.

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Review
What do each of these buttons do?

• Menus (and corresponding commands) used so far
• display
• describe
• codebook
• list
• generate
• replace
• by/if//in

What does each one do?
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Your turn again

• In Chapter 1 of the Stata guide, go through
• Section 1.6
• Section 1.7
• Section 1.8
• Ask a resource person if you are unclear about
• any parts of the above sections.

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Review again

• Explain to a neighbour why
• (3lt4) gives the value 1 in Stata
• (3gt4) gives the value 0
• They then explain to you why the expression
• 1 (agegt24) (agegt60)
• Recodes a column into the values 1, 2 or 3
• (Hint see Section 1.6 Fig 1.19 and 1.20 if you
  need help)

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Typing and editing commands

• Professional use of Stata for data analysis
• benefits by some use of Stata commands
• These are typed into the Command Window
• To execute a command just press ltEntergt.
• To edit a previous command
• Click on it in the review window,
• or use the Page-Up key perhaps repeatedly.
• In the Results Window
• A dot appears in front of executed commands
• whether generated by a dialogue, or by typing the
  command.

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Command for listing data

• In the command window, typing
• list region district household cluster
• will show the contents of each of the variables
  region, district, household and cluster.
• (Note Stata is case sensitive)
• Pressing the GO button (see Stata menu bar) or
  the space bar allows you to scroll down the page
• To stop the display, press the red break icon
  button or press the letter q on your keyboard.
• To exit Stata, use
• File ? Exit

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Your turn yet again

• In Chapter 2 of the Stata guide, go through
• Sections 2.1 and 2.2
• (You can go further if you have time)
• If you have your own data
• And it is not already in a Stata file, then
• In Chapter 3 of the Stata guide, go through
• Sections 3.2.1, 3.2.2, 3.2.3
• And discuss importing with the resource persons

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and finally

• Consider a data set from your own district or
  ministry that is available as an Excel file.
• Follow procedures similar to those in Section
  3.2.3 of the Stata Guide, to load your Excel data
  set into Stata.
• Save your data as a Stata file, giving it an
  appropriate name and noting the directory on your
  computer where it has been saved.
• Note You will return to this data set in
  sessions that follow.