Content Comparison

Column and Bar Charts

Used to show a comparison among different items

• Use consistent colors throughout the chart, and avoid adding extra colors unnecessarily
• The measure axis should typically start at 0 to avoid misleading viewers
• Use horizontal labels whenever possible to ensure that they are readable
• Consider using a bar chart over a column chart, when dimension axis labels are long
• Choose a bar chart over a column chart when displaying negative values
• Choose a column chart when comparing values over time

Line and Area Charts

Best for depicting trends or progress over time

• Utilize line charts for comparing measures or dimensions to each other
• Utilize area charts for showing cumulative values
• Choose stacked area charts for visualizing how different components contribute to the overall trend (avoid stacking line charts, as this is easy to misinterpret)
• Avoid plotting too many lines or categories at once (5 or fewer is best)
• When possible, it’s best to start the y-axis at 0 to ensure no misinterpretation of the data

Dual-Axis Charts

Best for visualizing relationships between different measures when the scale of each is vastly different (i.e. values and percentages)

• Combine different mark styles (such as a line and a bar) to clearly illustrate each measure
• Use contrasting colors for each measure to further clarify which is which
• Place the primary measure on the left-side y-axis, as people tend to look to the left first (similar to how they would read)

Pie and Donut Charts

Best used to visualize a part to whole relationship

• Make sure that the total sum of all segments equals 100 percent
• Include fewer than 5 categories in the pie or donut chart whenever possible
• Pie and donut charts should not be used for comparing individual sections to each other or for representing exact values
• Avoid pie and donut charts whenever possible, as differences in angles and areas can be difficult for the brain to detect