Recommendations for Creating Charts and Graphs - Appendix D

Guidelines for Creating Board Presentations


Appendix D


RECOMMENDATIONS FOR CREATING CHARTS AND GRAPHS

1. There are six basic types: 1) Line, 2) Bar, 3) Area, 4) Pie, 5) Scatter, and 6) High / Low / Close.
   1. Keep the color scheme the same as what you have for text slides. Make sure the colors you select translate well into black and white or grayscale for handouts. Remember, minimum text point sizes still apply for creating charts and graphs.
      
   2. Do not use the default legend. Hand label elements if necessary.
      
   3. Keep the number of data points to a minimum. If necessary find another way to represent the "trend" or whatever the take home message is.
      
   4. Minimize the use of 3-D or shadow effects on bars, pie charts and grid lines. These tend to make the slide busy and can take away from your message.
      
   5. Use a meaningful title, i.e., "Major Sources of PM10 in the Sacramento Valley (1990 - 1997)" would be preferred over "Sacramento PM10 Emissions."
      
   6. If you have a lot of bars on a bar chart, like for example for 15 years worth of data … don't label every bar with a date. Consider labeling every fourth bar for example. Usually the idea is to show relative values or trends, not absolute data for each year.
      
   7. Avoid presenting more than one or two concepts per slide. If you have more than two concepts, consider using additional slides or using a series of slides to show the complete message. Other wise, maybe consider using a handout for the actual data and then choosing another way to represent the trend or overall message. Sometimes it is most effective if you go back to words / bullets.
      
   
   
2. Line Charts (Samples in PowerPoint97):
   1. These are best for showing time series data, trends, large numbers of data points and data flow.
      
   2. Try to limit to four or five lines per chart.
      
   3. Color is the best distinguisher between lines. Use the same line color for each data set throughout your presentation. Don't switch colors between slides.
      
   4. Use 6 point size or greater for each line. You may need to change the default in your software or manually adjust point size to achieve this.
      
   5. Trend / Data lines should be thicker than axes lines which should be thicker than grid lines.       
      
   
   
3. Bar Charts (Samples in PowerPoint97):
   1. These are best for showing differentials between data at set moments in time and differentials in related data.
      
   2. Use darker colors and fills closer to the baseline of stacked bars and to the left of clustered bars. Use lighter colors towards the top and right of charts.
      
   3. Horizontal bars can be used to compare many items in a single series or when the X-axis labels are too long to fit nicely along the horizontal axis.
      
   4. Stacked bars are used to show totals and portions of totals rather than relative differences between data sets. They are very good for showing how portions of the totals may change over time.
      
   5. Clustered bars are best used to show relative differences between data sets rather than totals. Keep the number of bars in a cluster to five or less.
      
   6. Overlapping bars are used to group related data. These work especially well if the date values get progressively larger.
      
   7. Paired bars are used to show two series that share the same X-axis but not the same Y-axis.
      
   
   
4. Area Charts (Samples in PowerPoint97):
   1. These are useful for showing totals and not useful for showing change.
      
   2. The data set of greatest importance should be placed at the bottom.
      
   3. In stacked area bar charts place the data set with the greatest values in the back.
      
   
   
5. Pie Charts (Samples in PowerPoint97):
   1. These are used to show the relative proportions or composition of a total amount.
      
   2. Values used can be absolute or percentages.
      
   3. Portions, or "pie slices" and be "exploded" for emphasis but this technique should be used sparingly. You can successfully explode one or two pieces but more than that is distracting and usually takes away from your message.
      
   4. Variation including showing the exploded slice as a stacked bar.
      
   5. Try to limit the number of pie pieces to 6 or less.
      
   6. Place the most important piece in the top right hand quadrant.
      
   7. Arrange slices from the largest to the smallest in a clockwise direction.
      
   8. Keep labels short and hand label. Avoid using the software default key or legend. These may work fine for printed pages but they do not project well on presentation media.
      
   
   
6. Scatter Charts:

   These are limited to presenting raw data or unconnected data points.

   
   
7. High / Low / Close Charts:

   These are limited to the presentation of gross relativevalues such as high, low, average. These charts are used extensively in the presentation of financial data and only occasionally in the presentation of scientific data.