Distribution
Strip / jitter plot
Shows individual values within categories, with lateral offsets to reduce overlap.
- Plot
- Distribution
- Comparison
What it answers
How are individual values distributed within groups?
- Shape
- Individual points offset sideways
- What it shows
- Clusters, outliers and repeated measurements.
Example
The question
How do individual shift lengths spread in each team?
Hours worked per shift by team, one dot per shift (strip plot, illustrative)
Illustrative data. It belongs to no company.
When to use it
Use it when
Small-to-moderate raw samples and categorical comparisons.
Avoid it when
Severe overlap that requires binning or density instead.
How to read it
Read the value axis and ignore sideways jitter as measured data.
Note
Jitter does not encode another measured variable.
The data you need
- Layout
- Long table
- Fields
- Group: text; Value: number
- One row is
- One raw observation belonging to a group. What is the grain?
- Rules
- Retain individual observations and group labels. State weighting and missing-data rules.
- Optional
- For box plots only, some tools accept Group,Q1,Median,Q3,WhiskerLow,WhiskerHigh plus separate outliers. Other distributions usually need raw data.
- Preparation
- Keep raw numeric observations, group them if needed and handle missingness explicitly. Choose bins, bandwidth or summary conventions as appropriate to this specific plot.
- Units
- The measurement axis retains its original unit. Frequency uses observations; normalised frequency divides by group sample size; density also depends on interval width.
Worked example
Values 10,12,12,18,23. Jitter the two 12 s sideways. They remain at value 12; sideways displacement has no numeric meaning.
| Group | Value |
|---|---|
| A | 10 |
| A | 12 |
| A | 18 |
| B | 11 |
| B | 23 |