Visualizations > Hierarchy charts

Hierarchy charts

Hierarchy charts visualize a hierarchy, helping you to see patterns in your coding or view the attribute values of cases and files.

Create a hierarchy chart by clicking Hierarchy Chart in the Charts group on the Explore tab.

What can I show in a hierarchy chart?

Files

  • Compare the amount of coding of your files—are some files more heavily coded than others?
  • Identify files with most coding references at specific nodes—for example, which files contain the most coding references to Economy?

Nodes

  • Compare the amount of coding at your nodes—do some nodes contain more coding references than others?
  • Visualize prominent themes in your project
  • Identify areas that need further investigation or research

Attribute values

If you have classified your files or classified your cases, you can:

  • Check that you have consulted a variety of files—for example, have I relied too heavily on journal articles that are more than ten years old?
  • View the demographic spread of your survey respondents

Which type of hierarchy chart should I use?

Hierarchy charts are most useful when you want an overview of data that shows multiple levels of your hierarchy at once. Choose between the following:

Other visualizations in NVivo can more accurately show coding quantities—consider using a chart if you want to compare quantities for individual items.

How display options affect the chart

Hierarchy charts use size to convey meaning. You can use color to show additional information. This means you can size items in the chart to compare them by one metric, and then color the items to compare them by a second metric—in the same chart.

By default, hierarchy charts are sized by items coded, and colored by hierarchy. Use the Size By and Color By options on the ribbon to change the way data is displayed on the chart.

Understanding aggregation in a hierarchy chart

Hierarchy charts represent your data as aggregated. Even if you have not turned on node aggregation, any node with child nodes will be represented on a hierarchy chart as a parent node including its children.

When you hover over an area of the chart, a tooltip displays information for that item and specifies the number of items coded and number of coding references that relate directly to the parent, as well as an aggregated figure of parent plus children.

Hierarchy charts size a node based on whether or not it has children—therefore any node containing child nodes may appear larger than its actual coding. Use the tooltip information to understand the data underlying an area.

A tooltip displaying for a particular box in a tree map showing number of coding references and items coded