Hi there! In this 'Time to Viz' you will get to know everything about bar charts. There are many forms of the bar chart, sometimes even called 'column chart'. In essence, the bar chart represents values in a rectangular format, plotted on an axis.
Comparison method
Bar charts are used in visualizations to compare items over two possible dimension: time or category. Based on the dimension, the graph can be, and will be interpret differently.
Time: Used to figure out if there is a trend in the data, like a line chart. Examples could be to figure out a trend in sales, or to detect a change in stock volumes over time.
Category: Used to rank the data, and to see immediate high and low values. Examples could be to figure out which item category has sold the most item, or which segment out of five is containing the most customers likely to churn?
Even though the dimensions are totally different, the bar chart still feels familiar and is easy to read if you create it according to best practices. The bar chart allows the user to make simple comparison, and to achieve that insight instantly.
Types
For more complex comparisons, bar charts can be divided per dimension in two various types. This way the user gets the possibility to choose the right bar chart type, appropriate to the use case.
Grouped (clustered) bar chart: Chart used to which represents two or more bar per category group. Examples could be that a stakeholder would need to compare year-over-year per brand he is responsible for. the X axis would represent the brands, and the bar charts would represent the years.
Stacked bar chart: The stacked bar chart does what is says, it stacks the categorical values on top of each other. This is often seen in a 100% stacked bar chart, where the user sees how many % of the grand total is represented by a certain category.
Orientation
Orientation is often seen as something trivial, but is important when it comes to visualize data correctly and give the right vibe to your end user. The bar chart is one of the few visualizations that can be placed horizontally or vertically. Depending on the type and comparison method, it is better to choose a vertical or horizontal orientation. For example when data is compared to time in a simple bar chart, it is recommended to visualize this in a horizontal graph.
Hints and tips
Colour is an essential part of your visualizations, and colour can help the user to lead them to insights.
When comparing categories with each other, and one category is more important than others, recolour the category to stick it out.
Use different colours for different categories that do not belong to each other.
When ranking values in a bar chart, always sort the data from big to small, this immediately indicates which values are bigger/ smaller than others.
If possible, use data labels on your bars to show the values together with the bars.
If you are working with averages, targets, or benchmarks you can visualize these values in a line-bar chart, which is a combination of a bar chart and line chart. Do make sure that you have one Y-axis to avoid confusion.
Conclusion
Bar charts can be defined as a visual with many possibilities. They can be created as a clustered or stacked chart and can be compared to category or time dimensions. Orientation is important for this visualization, as this will give a different feeling to your end user, depending on the orientation. A bar chart can be customized in various ways, in order to present the right data to the right audience.
Source used for images:
https://datavizproject.com/