### Which Graphs and Charts Should You Use?

So your task is to write a business document, such as a report or brochure, or even a blog post. You have lots of information to present that could make your reader drowsy faster than a sleeping pill. What can you do to liven up your document? You can use graphs and charts to effectively communicate that information.

In my post, 12 Tips for Using Tables in Business Writing, I point out that visual communication is a great way to condense information and keep your reader interested.

In addition to tables, graphs and charts are a wonderful way to simplify complicated information, make your subject clearer, and add weight to key points. They have a favorable impact on your reader and help sell your ideas. Which graphs and charts should you use?

#### Choosing the right graphs and charts

There are many different types of graphs and charts. Let’s look at the three most common graphs and charts: the line graph, pie chart, and bar graph.

#### When to use a line graph

Use a line graph to show changes over different periods of time by means of a line. Hence, we use the name line graph.

It’s useful for showing trends. It also shows how two variables – that have continuous scales on both the vertical and horizontal axes – relate to one another. In the example below, we have the number of correct answers (vertical axis) a learner got over 4 days (horizontal axis). Notice how the line graph below is more effective in presenting information than the table.

##### Example showing number of correct facts

Table: Facts I got Correct |
|||

Day 1 | Day 2 | Day 3 | Day 4 |
---|---|---|---|

3 | 4 | 12 | 15 |

And here is the same data as a Line Graph:

Source: Pierce, Rod. (14 Jan 2014). “Line Graphs”. Math Is Fun. Retrieved 30 Mar 2014 from http://www.mathsisfun.com/data/line-graphs.html

#### When to use a pie chart

Use a pie chart when you want to compare parts of a whole that has a finite total. It shows the distribution of percentages. The whole pie represents 100% of the data. Each segment of the pie represents a particular percentage of the whole. Notice how easy it is to read the pie chart because it shows what portion of the pie goes to each grade. It is much more effective than the table.

##### Example showing student grades, ranging from A to D, on a test

A |
B |
C |
D |

4 | 12 | 10 | 2 |

And here is the pie chart:

Pierce, Rod. (14 Jan 2014). “Pie Chart”. Math Is Fun. Retrieved 30 Mar 2014 from http://www.mathsisfun.com/data/pie-charts.html

#### When to use a bar graph

Use a bar graph to to compare different things and show relative sizes – the higher the bar the greater the value. Bar graphs are useful because they can be subdivided. For example, in the bar graph below we can compare male and female viewers or different years.

##### Example from a survey showing viewers’ favorite movies

Table: Favorite Type of Movie |
||||

Comedy | Action | Romance | Drama | SciFi |
---|---|---|---|---|

4 | 5 | 6 | 1 | 4 |

Here is the same information shown more emphatically in a bar graph:

This bar graph clearly shows, at a glance, which type of movie viewers like best and which they like least. Note that you can also show data horizontally rather than vertically, if you prefer to show the legend (the types of movie) on the right side of the graph.

Pierce, Rod. (23 Mar 2014). “Bar Graphs”. Math Is Fun. Retrieved 30 Mar 2014 from http://www.mathsisfun.com/data/bar-graphs.html

Now you know better which type of graphs and charts to use the next time you need to write a business document.