Session 1

1. Session 1 Module Introduction and Getting Started with Stata

2. Introduction Welcome Housekeeping Introductions Name, job, district, team 2

3. 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.

4. 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. 4

5. Duration and timetable 5

6. 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 6

7. Prerequisites Completion of Modules 1 and 2 At least a theoretical knowledge of statistical inference 7

8. 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 8

9. 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

10. 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

11. 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

12. The four Stata windows Review Stata Results Variables and window for typing Stata commands

13. 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

14. Check Stata is up-to-date • Use Help => 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

15. The Data and Graphics Menus

16. 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

17. 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

18. Using Stata as a calculator Type 2+3 into the Expression slot Press the Submit button To perform calculations, use Data  Other utilities  Hand calculator See answer in Results Window, and appearance of corresponding command in both the Results and Review windows.

19. 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

20. Creating an expression Click create and then complete the resulting expression builder dialogue box. Or type: display ln(10)

21. 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 => Change working directory • To set this directory for the future

22. 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?

23. Options within the Data menu

24. An example of a dialogue box Dialogue results from using the menu sequence Data,  Describe data, Describe data contents (codebook)

25. 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

26. Another dialogue box Dialogue results from using the menu sequence Data, Describe data, Summary statistics

27. Results from codebook and summarize

28. 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.

29. 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?

30. 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.

31. Review again • Explain to a neighbour why: • (3<4) gives the value 1 in Stata • (3>4) gives the value 0 • They then explain to you why the expression: • 1 + (age>24) + (age>60) • 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)

32. 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 <Enter>. • 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.

33. 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

34. 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

35. … 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.