By Tanya Arya
As our world is becoming increasingly data-driven, it’s more important than ever to have accessible ways to view and understand data. Demand for data skills in employees is steadily increasing each year. Employees and Business owners at every level need to understand data and its impact. With the emergence of big data, it is becoming even more difficult to comprehend data. This is where graphs and charts come in, but is it true that all graphs are helpful?
Pie charts are circular charts showing an area proportionate to the total. They are useful in some cases but there are many downsides to them like their complexity, intelligibility, and their tendency to take too much space. This article explains why pie charts are evil and pointless, although they could be called pointless even if they were useful.
What is Data Visualization?
Data visualization is translating information into a visual context, such as a map or graph, to make it easier for the human brain to understand and pull insights from the data. It provides a way for employees and owners to present data to non-technical audiences without confusion. In today’s world, it has become difficult to find data that is not big data. Big data contains greater variety and has a huge volume with more velocity. They are larger and more complex datasets, especially from new data sources. These datasets are so huge that traditional data processing software is not capable of managing them. This big data, although tedious to compute, can also be used to address business problems that could not be tackled before. Big data has been used in machine learning, predictive modelling, and other advanced analytics to solve business problems and make informed decisions. No one can trace the origins of big data but some say it emerged in the 1990s, crediting the American computer scientist John R Mashey, considered the ‘father of big data’, for making it popular.
This is where data visualization comes in handy, it is used to analyze large amounts of data and massive amounts of information and make data-driven decisions. Our eyes are drawn to colours and patterns and data visualization turns this into a benefit. We can identify red from blue, different shapes from each other and visually understand the differences in amounts of objects. Human culture is visual, everything from art to advertisements on TV, and data visualization gives us the power to harness this and use it for data that is illegible to understand. When we see a chart, we can quickly see the trends and outliers and can internalize them quickly. Data Visualization is also useful for easily sharing information, interactive exploring opportunities, and visualizing patterns and relationships.
What are Pie Charts?
A pie chart is a circular graph that represents data. The slices of this circle are the “pies” which represent specific categories. The slices of a pie show the relative size of data concerning he circle, and it is a type of pictorial representation of data. A pie chart requires a list of numerical and categorical variables. The pie chart is known as a “circle chart”, dividing the circular statistical graphic into sectors or sections known as “pies” to illustrate numerical problems. Each sector or slice denotes a proportionate part of the whole. Pie charts are used to find out the composition of something and can be used to replace other graphs like bar graphs, line plots, histograms, etc. The sum of the data is equal to 360 degrees and the total value of the pie chart is always 100%. It helps organize data as a percentage of a whole. This type of chart helps the user compare the relationship between different dimensions (Ex. categories, products, individuals, countries, etc.) within a specific context. Here, an example of a pie chart can be seen showing income tax collections in the year 1995-96. The green is with a proportion of 49% is the amount of corporate tax in proportion to the total tax collections, the blue area with a proportion of 47% is the amount of personal income tax in proportion to the total tax collections, and the yellow area with a proportion of 4% is the amount of other direct taxes in proportion to the total tax collections.
Year | Corporate Tax | Personal Income Tax | Other Direct Taxes | TOTAL |
1995-96 | 16487 | 15592 | 1485 | 33564 |
Why are Pie Charts EVIL?
As we have seen, there are advantages to pie charts, but the disadvantages outnumber them. Some of these disadvantages are:
They take up too much space:
Whenever you are visualizing data, you have limited space to work with. Either in the confines of a power point slide or in a word document. You must fill that tiny amount of space with the most value for the reader. Pie and donut charts use more space than alternatives that provide the same value as bar graphs and histograms. This is due to the nature of their shape which is a circle and how they depict information. The legend for a pie chart takes up too much space whereas a bar graph doesn’t require the same kind of legend. The circle shape of these charts creates an unnecessary amount of space around the chart.
As we can see here, the amount of space around the chart object for the pie chart has not been utilized in the same way that the bar graph has been.
They are not as readable as the other types of graphs:
Graphs are useful when a picture of the data makes meaningful associations visible such as patterns, trends, and exceptions that cannot be easily understood from a table of the same data. When looking at a pie or donut chart, it is difficult to discern how much larger one portion of the data is than the other since we know that the human eye is more, and the mind are much better at comparing distance rather than area.
This pie chart is the credit disbursed in India for 2022-23 in all the different states. Here, we can see how difficult it is to discern one slice from another, due to both the colour and the area. There is little difference in colour which may lead to mistaking one state for another, and the slices are so small that you cannot even tell which state is represented by them. You can also see the amount of space that it has taken up on this page without providing any advantage in the same.
Overly complex:
Pie charts cannot convey more information without being overly complex. They do not allow a wide range of options for additional data points such as bar graphs. There are several ways to include additional data points in bar graphs and other types of graphs as well that do not look too crowded or hard to read. The same can be said for 3D renders for pie charts. They do not add additional information but just add complexity and distort the information by showing a slice far away as smaller and vice versa for a slice of the pie closer to you.
This bar graph has 5 years of income tax collections in India that it is covering along with 3 categories of the type of tax that is being collected. This kind of information cannot be conveyed on a pie chart. For the same kind of information in pie chart we would need 5 pie charts for all the five years which can be seen here:
These 5 pie charts although are easy to understand but they take up a lot of space. Other direct taxes in all of them is basically invisible and it is not a viable method to understand a comparison of year wise data for income tax collections.
This is a 3D render of the pie chart. Due to this being 3D, it completely distorts the information provided. Your human brain now, does not have to just comprehend the angles of these slices but also adds one more dimension which makes it extremely difficult.
This gives us a basic understanding of why pie charts are evil. For efficiency in the workplace or in a classroom, pie charts are not viable. Their limited intelligibility, complexity, and tendency to take too much space does not make them helpful to understand. Despite the well-known problems with pie charts, they are still heavily used by policymakers and statisticians. One reason might be their popularity which is a circular argument suitable for pie charts. Due to the arguments made here, you could pretty much say that pie charts in this modern world are pointless
Notes:
About the Author:
Tanya Arya is a Sub-Head for the Research Department and third year economics student (UG) at JSGP. She is also the female COGSASH representative for JSGP.
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