Table manners

1. GAP Toolkit 5Training in basic drug abuse data management and analysis Table manners Training session 10

2. Objectives • Define the common terminology used to evaluate survey data • Establish the information that should be reported with the data, whether the data take the form of a table, a graph or numerical summaries • Introduce the Output Viewer in SPSS • Describe formatting charts and tables

3. Conflicting aims • A table has two purposes: • To put across a point • To allow the reader to verify our claims with reference to the data • “These aims are not always the same and getting the balance right is as much an art as a science.” (C. Marsh, Exploring Data: An Introduction to Data Analysis for Social Scientists (Cambridge, Polity Press, 1988)).

4. Survey terminology • Reliability • Validity: • Internal • External

5. Reliability • A tool of measurement displays reliability if it records the same result in repeated applications under identical conditions • For example: • I weigh myself on my bathroom scales on Monday and weigh 100 kg • I weigh myself on my bathroom scales on Tuesday and weigh 72 kg • This would be nice, but is unlikely: the scales are probably unreliable

6. Validity • Validity takes various meanings in survey design • Internal validity is the ability of the measure (the question or observation) to adequately represent the underlying concept of interest

7. External validity • External validity refers to the ability to abstract generalizations from the results: • Are the data from a sample? • If “yes”, is that sample a reasonable representation of the population? • If so, can the results be generalized to the population?

8. Table design • Clarity: • Structure • Message • Completeness

9. Titles • Who/What? • When? • Where?

10. Source • It is essential that the source of the data is presented regardless of what form the statistics take • The source of the data helps establish the authority of the data

11. Variables • Definitions • Units

12. Percentages • If a variable is measured in percentages, be certain it is clear what it is a percentage of: • Rows • Columns • Totals • Ensure that the original numbers can be calculated by reporting the sample size (the size of the denominator in the calculation of the percentage)

13. Method • Sample statistics are frequently used to make general statements about the population • If the statistics are drawn from a sample, state the method of sampling • The method determines the external validity of the results

14. Missing data • Always report the number of missing observations in your data set • A large amount of missing data brings into question the external validity of a survey: • Those who agreed to answer and those who refused may well have different characteristics

15. Precision • Avoid reporting data to unjustifiable levels of precision • Round results to the level of precision of the original data

16. Output Viewer • The third main window in SPSS • Used to edit and format the results of any statistical analysis • Generates output files with the suffix .spo

17. Exercise: Session 8: Output • Retrieve the output file “Session 8 freq.spo” saved in session 8

18. Output Table of contents

19. Left-hand panel • Use the left-hand panel to manage the output • Clicking on a heading selects that part of the output • Clicking on the – sign to the left of a heading hides or collapses the output • Clicking on the + to the left of a heading displays or expands the output

20. Right-hand panel • Select a single piece of output by pointing and clicking once • Select multiple pieces of output by holding down the Ctrl key while clicking more than once • Format output by pointing and double-clicking

21. Copying tables to Word • Select the output in the left-hand panel or in the Viewer • Edit/Copy • Move to Word • Edit/Paste Special: • Formatted Text • Unformatted Text • Picture

24. Copying charts to Word • Select the output in the left-hand panel or in the Viewer • Edit/Copy • Move to Word • Edit/Paste

25. Exercise: copying to Word • Copy the frequency table for Education to a Word document as: • Formatted text • Unformatted text • Picture • Copy the bar chart of Education to the same Word document as a picture

26. Formatting tables • Double click to enter formatting mode • A new border appears around the output with short diagonal lines at a 45-degree angle • The menu bar now contains formatting options

27. Editing the table • Edit any component of the table by double-clicking that particular part of the table • A box will appear in which the table can be edited

30. Race of clients: treatment centres in the Cape region of South Africa January-June 2001

31. Insert • Insert/Title • Insert/Caption • Insert/Footnote

33. Caption text box

34. Type required caption here

35. Race of clients: treatment centres in the Cape region of South Africa January-June 2001 Source: The data were collected from the treatment centres as part of the South African Drug Information System.

38. Race of clients: treatment centres in the Cape region of South Africa January-June 2001 a Source: The data were collected from the treatment centres as part of the South African Drug Information System. a Note that the small number of Asian clients raises issues of the generalizability of the results pertaining to the Asian community.

39. Format • Format/Table Properties • Format/TableLooks

40. TableLooks

41. Race of clients: treatment centres in the Cape region of South Africa January-June 2001 Source: The data were collected from the treatment centres as part of the South African Drug Information System. a Note that the small number of Asian clients raises issues of the generalizability of the results pertaining to the Asian community.

42. Formatting charts • Double-click a chart in the Output Viewer to open the chart in the Chart Editor • To edit or format the chart: • Point at the part to be edited and double-clickOR • Use the menu bar options