1. Presenting Data in Charts, Graphs and Tables #1-8-1

2. Purpose of Displaying Data v The purpose of developing clearly understandable tables, charts and graphs is to facilitate: © analysis of data © interpretation of data © effective, rapid communication on complex issues and situations #1-8-5

3. Types of Variables v Categorical variables refer to items that can be grouped into categories. © Ordinal variables are those that have a natural order. © Nominal variables represent discrete categories without a natural order.  Dichotomous variables have only two categories v Continuous variables are items that occur in numerical order. #1-8-6

4.  Simpler is better.  Graphs, tables and charts can be used together.  Use clear descriptive titles and labels.  Provide a narrative description of the highlights.  Don’t compare variables with different scales of magnitude. #1-8-7 General Rules for Displaying Data

5.  A diagram shown as a series of one or more points, lines, line segments, curves or areas  Represents variation of a variable in comparison with that of one or more other variables #1-8-8 Graphs

6. Scale Line Graph v Scale line graph: represents frequency distributions over time v Y-axis represents frequency. v X-axis represents time. #1-8-9

7. #1-8-10 Year Figure 8.1. Trends in HIV prevalence among pregnant women in Country X, years 1 – 10 Example: Scale Line Graph

8. Specific Rules: Scale Line Graphs v Y-axis should be shorter than X-axis v Start the Y-axis with zero v Determine the range of values needed v Select an interval size #1-8-11

9. Bar Charts v Uses differently coloured or patterned bars to represent different classes v Y-axis represents frequency v X-axis may represent time or different classes #1-8-12

10. Example: Bar Chart Figure 8.2. Differences in HIV prevalence among various high-risk groups, Country X, year 1. #1-8-13

11. Specific Rules: Bar Charts v Arrange categories that define bars in a natural order (for example, age). v If natural order does not exist, define categories by name, such as country, sex or marital status. v Position the bars either vertically or horizontally. v Make bars the same width. v Length of bars should be proportional to the frequency of event. #1-8-14

12. Histograms v A representation of a frequency distribution by means of rectangles v Width of bars represents class intervals and height represents corresponding frequency #1-8-18

13. Example: Histogram #1-8-19 Figure 8.4. Children living with HIV, District X, 2002

14. Pie Charts v A circular (360 degree) graphic representation v Compares subclasses or categories to the whole class or category using differently coloured or patterned segments #1-8-20

15. #1-8-21 Example: Pie Chart Figure 8.5. Projected annual expenditure requirements for HIV/AIDS care and support by 2005, by region

16. Tables #1-8-24 v A rectangular arrangement of data in which the data are positioned in rows and columns. v Each row and column should be labelled. v Rows and columns with totals should be shown in the last row or in the right-hand column.

17. #1-8-25 Table 8.1. Adults and children with HIV/AIDS by region in Country Y, end year X Example: Table RegionAdults and adolescents ≥ 15 years Children <15 yearsTotal 114 80020015 000 2400 00020 000420 000 3997 0003 0001 000 000 4985 00015 0001 000 000 51 460 00040 0001 500 000 6465 00035 000500 000 7940 00010 000950 000 8380 000220 000600 000 9900 000600 0001 500 000 10545 0005 000550 000 Total7 086 800948 2008 035 000

18. In Summary v Data can be analysed by person, place or time. v Depending on your data, you can choose from a variety of chart and graph formats, including pie charts, histograms, tables, etc. v Using several simpler graphics is more effective than attempting to combine all of the information into one figure. #1-8-26