Data Visualization Best Practices : Part 2 – Choosing line chart or Bar chart.

Line and bar charts are the most common type of charts used in BI reports and dashboards. In the given figure below there are three line charts. Try to figure out which of these charts are inappropriate.

Line charts should be used when quantitative variables change over a period of time, as it help’s in discovering trends.
In the first two charts the x axis is represented by categorical variables which are nominal (Chart A) and ordinal (chart B) in nature.
Bar Chart are preferred for qualitative variables as they help in making comparison across different categories.
In the first two charts bar chart should be used instead of line chart, as trends across different categories does not help in decision making.
Third chart(chart C) helps in discovering upward trend for the measure used over a period of time. So line chart should be preferred based on best practices.

For given dataset different visualizations can be used but not all visualization helps in making better decisions. So it’s recommended to follow best practices.

In the next post we will post series of charts and you have to decide which chart type to use based on best practices.

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