What is a pie chart?

A pie chart reflects the relationships of components to the entirety for a variable.

How are pie charts used?

Pie charts assist you understand the parts-to-a-whole relationship. Pie charts are frequently used in other situations, also if bar charts or heat graphs could be a much better choice. 

What are some issues come think about?

Pie charts are provided for nominal or categorical data. When over there are countless levels to her variable, a bar graph or pack bar chart may administer a better visualization of your data. 


Pie charts present the parts-to-whole relationship

A pie graph is a circle that is divided into areas, or slices. Each part represents the count or percentage of the observations the a level for the variable. Pie charts are frequently used in business. Examples incorporate showing percentages of species of customers, portion of revenue from different products, and also profits from various countries. Pie charts can be useful for showing the relationship of parts to the whole when there space a small variety of levels. Because that example, a good pie chart could show how various brands of a product line contribute to revenue, as seen in figure 1.

You are watching: A ________ shows the relationship of each part of the data to the whole.


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figure 2: basic pie chart

Example 2: Bar chart shows similar values

When worths for a parts-to-whole partnership are an extremely similar, pie charts space not the best choice. Look in ~ the pie chart for the Titanic in Figure 2. As soon as the score is to show "nearly half" of the passengers to be in either first or 2nd class, the pie chart is helpful. Once the goal is to show an ext detail, a bar chart is simpler to visually interpret. The graph in number 3 shows the same data plotted in a bar chart.


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number 4: Pie chart with many categories

In a pie with so plenty of slices, it difficult to process the details of the parts-to-whole relationship. Also, as in Figure 2, the difference between an in similar way sized categories is complicated to distinguish. For example, room there more Thriller or computer animation movies? It’s difficult to identify from a pie chart. 

Figure 5 is a bar chart for the exact same data. 


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figure 5: Data from number 4 plotted in a bar chart

The bar chart mirrors the parts-to-whole partnership for the plenty of genres much better than the pie chart. We can likewise see that there are an ext Thrillers than animation movies. We could further boost this bar chart by adding labels to the bars, or by sorting the bars in order of percentages rather of in alphabet order. In number 6, a sorted bar chart quickly illustrates the parts-to-whole relationship and also the fact that over there are much more Thrillers than animation movies.


figure 6: Bar chart sorted by percentage

Example 4: Use many pie charts to show alters in parts-to-whole relationships

Multiple pie charts are valuable when the goal is come show changes in parts-to-whole relationships, particularly when the score is not to focus on certain details. Figure 7 shows historical data for smart phones, starting when the an initial smart phones were released in 2006. Each pie reflects the parts-to-whole relationship of market share by operating system for a specific year.

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number 7: Pie charts showing changes in parts-to-whole relationship

We have the right to see just how the home windows operating device started the end as half of the sector share in 2006 and ended with a much smaller sector share in 2011. Similarly, we can see that the Android operating mechanism was no in the market until 2008 and comprised more than fifty percent the sector by 2011. The goal below is to display the parts-to-whole relationship changing over time. If the goal is to show the alters over time because that each operation system, a line graph is a far better choice. 

Pie charts and varieties of data

Categorical or in the name of data: proper for pie charts

Pie charts make sense to present a parts-to-whole relationship for categorical or in the name data. The slices in the pie commonly represent percentages of the total. 

With categorical data, the sample is often divided into groups and the responses have a defined order. For example, in a survey where you are asked to give your opinion on a range from “Strongly Disagree” to “Strongly Agree,” her responses are categorical.

Wtih nominal data, the sample is additionally divided right into groups yet but without any particular order. Country of residence is an instance of a in the name of variable. You can usage the country abbreviation or you deserve to use number to code the country name. Either way, girlfriend are merely naming the different groups the data. 

Continuous data: choose another chart type

Usually, pie charts do not make sense for constant data. Since constant data room measured on a scale with many feasible values, showing a parts-to-whole connection does not make sense. Some instances of constant data are: