INFORMATION TECHNOLOGY

Seven visual elements, and when to use them

July 18, 2007

	Alert icon. This is a geometric shape, such as a circle, usually color-coded. Use when you need a dense cluster of indicators that are clearly labeled. These icons are also good for showing system state.
	Traffic light. A simple extension of the alert icon. In most cases, an alert icon is a better choice. However, the traffic light is a familiar symbol for showing good, bad, or warning states. Users may understand the information faster.
	Trend icon. Shows how an element behaves over time. Many symbols can be used to show trends, including arrows or numbers.
	Progress bar. Indicates progress along an axis toward a positive quantity or real number. This icon doesn’t work well for showing negative values.
	Gauge. A good indicator for showing positive or negative values along a relative scale. These icons should be reserved for the most critical metrics because they tend to focus user attention.
	Pie chart. Shows percentages or shares. The icon shouldn’t be used for more than six elements. Ideal for small data sets that are geared to high-level relationships, not details.
	Bar chart. Designed to show relationships between data elements within a series. Because the bars share a common measure, it’s easy to compare data elements. They are best used for categorical analysis or small time-series analysis.