Understand the meaning and purpose of the most common chart types
I would like to take this opportunity to explain how PowerPoint utilizes another Microsoft program when you request it to
create a chart for you all "behind the scenes"!
First, it is important to understand the differences between these two applications. Any time you insert a chart in
PowerPoint, or you select one of the layouts that contains a placeholder for a chart, PowerPoint automatically opens up
another Microsoft program called "Microsoft Graph".
This application is the same one that allows you to transform a spreadsheet into a statistical graph in Microsoft Excel. MS
Graph is part of the Office suite.
In PowerPoint, you might notice that something changes when you insert a new chart or double-click on an existing one. All of
your typical PowerPoint toolbars and menus are subtly replaced by different ones. It is also true that as soon as you click
outside of the chart area you are working on, PowerPoint takes over again and the toolbars and menus switch again.
Let me clarify all of this for you. It should be evident that any time you want to edit or transform an existing chart, you
need to double-click on the chart itself in order to open the Microsoft custom tool for charting. Though you do not actually
see it (unless you pay attention to the above-mentioned details) you are actually working with a different application
with its own characteristics and peculiarities.
The chart style offered by default when using this application, called Microsoft Graph, is called "column".
Once you are in the editing mode (that is, after double-clicking on the chart) you can change the chart style simply by
clicking on "Chart" in the Menu bar and choosing "Chart types..."
A dialog box will appear, with two tabs:
"Standard types" and "Custom types".
While I will describe in detail the "Custom types" in the December issue of MasterView, I will review here the most
useful standard types explaining when they can be used.
Column charts:
This is the default format any time you create a new chart in PowerPoint. Column charts use vertical bars (called columns) to
display different values of one or more items. They are used to compare values across categories. They are ideal for showing
the variations in the value of an item over time (e.g. budget).
According to symbolism and graphic principles, they better suit the visualization of data which are related with
height. For example, if I want to compare the volume or quantity for any product or item, I would use this format.
Bar Charts:
Bar charts are almost the same type as column charts. The difference is that they use horizontal bars instead of
vertical ones.
Bar charts compare values across categories and are ideal for showing the variations in the value of an item over time, or
for showing the values of several items at a single point in time.
They can be used to compare different distances or speed, since the horizontal layout helps the human eye to better imagine
what they represent. For example: you want to show how Lamborghini performs compared to Ferrari and Lotus. You want to
display their performance related to maximum speed, acceleration and gasoline usage. The better chart type to use
in this case is a bar chart. It can visualize all the data through its horizontal bars, giving your audience a symbolic
representation of their performance.
Another good reason to use bar charts is when you realize that the number of data series better fits in a horizontal format.
PowerPoint prints and displays the slides in landscape
orientation. So if you have long gaps between different values
and you have also many items to compare, the bar chart type is
the best one to use.
Line Charts:
Line charts do not perform very well in PowerPoint. Even though
you set the thickness of the lines to the maximum size, the
lines will still be too thin to produce an effective design.
Nevertheless, these charts are very useful to show a temporal
trend over time and are often used to show variations in the
value of more than one item over time.
Imagine you want to compare the grades of your students over
their college career. You may want to use the line chart since
it will show, with different line colors and styles, the values
of the single grades each student obtained during a lapse of
time. In this case, you will have different points in your plan
showing the different grades corresponding to the different
years of study. The line chart will just connect for you these
points using straight lines.
Pie Charts:
Pie charts are a very effective way to display information when
you want to represent the different parts of a whole, or the
percentages of a total.
Pie charts display the contribution of each value to a total
Pie graphs can represent only one data series (one row or
column of data only).
Many examples can be found for this chart type: when you want
to display how the parliament of one country is divided into
the different political parties (each political party will be
assigned either with the number of seats or with its
percentage. Each slice or sector of the pie will show this
value. All the values for all the slices, together, will make
the total).
For instance, you can use the pie chart to compare the
different countries of origin of a class of students, or the
allocation of the yearly budget to different sectors of
your company.
The pie chart, both in 2-D and 3-D, gives you the useful option
to extrapolate a single slice from the pie to better stress its
value by displaying it separated from the other slices.
An option that you will find for almost all of the chart types
is the "stacked" version of charts. Using this method, values
that are compatible or similar can be added on the same column
or bar. In the example about Lamborghini and Ferrari, you can
have only one column or bar for each model of car, and within
the specific column you will see three different values, the
maximum speed, the acceleration and the gasoline usage. In a
few words, you have a comparison between the contribution of
each value to a total, across time or categories.
You can read this article in the original issue of MasterView.
