Box plots

The box plot is suitable for comparing range and distribution for groups of numerical data, illustrated by a box with whiskers, and a center line in the middle. The whiskers represent high and low reference values for excluding outlier values. You can define the box start and end points, and whiskers ranges with a few different presets, or define your own settings using expressions.

Number of columns (dimensions and measures)

In a box plot you need to use one or two dimensions, and one measure. If you use a single dimension you will receive a single box visualization. If you use two dimensions, you will get one box for each value of the second, or outer, dimension.

Default settings for a box plot

Most native Qlik Sense chart types are automatically sorted on the dimension content:

  • Numeric content is numerically sorted.
  • Categorical content is alphabetically sorted.

Box plot elements

You can use one of the three presets to define your box plot. These are defined in the calculations object.

  • Standard (Tukey)

    This preset is based on the original box plot definition by J. Tukey. The center line represents the median (second quartile), and the box start and end points represent the first and third quartiles. Whisker length can be set to 1, 1.5 or 2 inter-quartile ranges. An inter-quartile range represents the distance between two adjacent quartiles, for example, the first and the second quartiles.

    "mode": "tukey"

    The whisker length is set in "parameters": {"tukey": 1.5}, where the number indicates the whisker length:

    • 1: 1 interquartile range
    • 1.5: 1.5 interquartile range
    • 2: 2 interquartile ranges

  • Percentile-based

    This preset is also defined with the box start and end points representing the first and third quartiles, and the center line representing the median, but the whisker length is adjusted by setting a percentile based whisker position.

    "mode": "fractiles"

    The whisker length is set in "parameters": {"fractiles": 0.01}, where the number indicates the whisker length:

    • 0: Min/max. This setting sets the whisker start and end points to the minimum and maximum values.
    • 0.01: first/ninety-ninth percentile
    • 0.05: fifth/ninety-fifth percentile
    • 0.1: tenth/ninetieth percentile

  • Standard deviation

    This preset is based on standard deviations, with the center line representing the average value, and the box start and end points representing one standard deviation variance. You can set the whisker length to a multiple of standard deviations.

    "mode": "stdDev"

    The whisker length is set in "parameters": {"stdDev": 3}, where the number indicates the whisker length:

    • 2: one standard deviation
    • 3: two standard deviations
    • 4: three standard deviations

You can also define a custom box plot where you set the value of each box plot element using an expression.

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