Icon Array
A grid of identical icons where a highlighted subset shows a proportion — one of the most intuitive ways to communicate risk and probability to any audience.
// 01 — The chart
What it looks like
Each icon represents one person in a population of 100. The 23 highlighted icons show the proportion affected — instantly graspable without any math.
// 02 — Definition
What is an icon array?
An icon array (also called a pictographic array or unit chart) is a grid of identical symbols — typically human figures — where a subset is visually highlighted to represent a proportion, probability, or percentage.
Unlike pie charts or bar charts that use abstract shapes and require mental estimation, icon arrays use discrete, countable units. You can literally count the highlighted icons to verify the number. This makes them exceptionally effective for communicating with general audiences, especially in healthcare, risk communication, and public policy.
Research consistently shows that icon arrays reduce denominator neglect — the tendency to focus on numerators and ignore the base population — because the full population is always visible.
Research finding: Studies in medical decision-making show that patients understand risk significantly better when presented as icon arrays compared to percentages or bar charts alone.
// 03 — Anatomy
Parts of an icon array
// 04 — Usage
When to use it — and when not to
- Communicating risk or probability to a general audience (e.g. '23 out of 100')
- Your audience is not data-literate — icon arrays require no chart-reading skill
- Showing a single proportion or comparing two proportions side by side
- Making health statistics, policy data, or safety information intuitive
- You want to humanize data — person-shaped icons make abstract stats feel real
- You need to show many categories simultaneously — use a bar or pie chart instead
- The proportions are very small (1 in 10,000) — too many icons to display practically
- You need to show trends over time — icon arrays are for snapshots, not time series
- Precise comparison between similar proportions is needed — use a bar chart
- Space is very limited — icon arrays require room to lay out individual icons
// 05 — Reading guide
How to read an icon array
Identify what each icon represents
Each icon stands for one unit — typically one person, one case, or one percentage point. The title or caption will tell you.
Count the total
The full grid represents the whole population or 100%. Common layouts use 100 icons (10×10 grid) so each icon equals 1%.
Look at the highlighted portion
The colored or differently styled icons represent the proportion of interest. You can count them or read the label to get the exact number.
Compare to the whole
The visual ratio of highlighted to total icons gives you an immediate sense of the proportion — roughly a quarter, about half, etc.
If comparing two arrays, look for differences
When two icon arrays are placed side by side, compare the highlighted areas to see which group has a higher proportion.
// 06 — Data format
What the data looks like
Icon arrays need just two numbers: the total population size and the count or proportion of interest. For a 100-icon grid, you simply need the percentage to highlight.
| Metric | Value |
|---|---|
| Total population | 100 icons |
| Affected count | 23 icons highlighted |
| Proportion | 23% |
// 07 — Construction
How to build one
Choose a grid size — 100 icons (10×10) is standard for percentage-based data.
Select an icon shape: human figures for population data, circles or squares for abstract data.
Arrange icons in a regular grid with consistent spacing.
Highlight the subset of icons representing the proportion — use a bold, contrasting color.
Add a clear title, the exact count/percentage, and a legend explaining what highlighted vs unhighlighted means.
// 08 — Common mistakes
Mistakes to avoid
Using random icon placement
Scattering highlighted icons randomly across the grid makes counting harder. Group them together (e.g. top-left to bottom-right) for clarity.
Too many categories in one grid
An icon array works best for 1–3 categories. More than that and the grid becomes a confusing patchwork of colors.
Inconsistent icon sizes
Making some icons larger or smaller to indicate importance undermines the array's core principle: each icon = one equal unit.
Omitting the total count
Always label the total number of icons. Readers need to know whether each icon represents 1 person, 10 people, or 1,000.
// 09 — In the wild
Real-world examples
Medical risk communication
Showing patients that '3 out of 100 people experience side effects' — far more effective than saying '3% risk'.
Public health campaigns
Illustrating vaccination rates or disease prevalence in a way that general populations can instantly understand.
Election and polling data
Showing what fraction of a population supports a policy using grids of person icons, making abstract polling numbers tangible.
// 10 — Quick reference
Key facts
Also known as
Pictographic array, unit chart, isotype grid
Category
Part-to-whole
Best for
Risk communication, health data, proportions
Standard grid
10×10 (100 icons = 1% per icon)
Key strength
Intuitive for non-technical audiences
Max categories
1–3 highlighted groups per grid
// 11 — Accessibility
Making it accessible
Use high-contrast colors between highlighted and unhighlighted icons (aim for 4.5:1 contrast ratio).
Add text labels stating the exact count and proportion — don't rely on counting alone.
Provide alternative text describing the icon array's meaning for screen reader users.
Consider adding a pattern fill (hatching, dots) to highlighted icons for colorblind users.
Group highlighted icons together rather than scattering — makes the visual pattern clearer for all users.
// 12 — Variations
Chart variations
Isotype Chart
Uses pictographic icons where each icon represents a fixed quantity — scaled icons rather than highlighting a subset.
Multi-category Icon Array
Uses different colors to show 3+ categories within the same grid — like a waffle chart but with shaped icons.
Randomized Icon Array
Scatters highlighted icons randomly to avoid grouping bias — used in some clinical research contexts.
// 13 — FAQs
Frequently asked questions
What is an icon array?+
An icon array (also called a pictographic array or unit chart) is a grid of identical symbols — typically human figures — where a subset is visually highlighted to represent a proportion, probability, or percentage.
When should you use an icon array?+
Use an icon array when communicating risk or probability to a general audience (e.g. '23 out of 100'). It also works well when your audience is not data-literate — icon arrays require no chart-reading skill, and when showing a single proportion or comparing two proportions side by side.
When should you avoid an icon array?+
Avoid an icon array when you need to show many categories simultaneously — use a bar or pie chart instead. It is also a poor fit when the proportions are very small (1 in 10,000) — too many icons to display practically, or when you need to show trends over time — icon arrays are for snapshots, not time series.
What data do you need to make an icon array?+
Icon arrays need just two numbers: the total population size and the count or proportion of interest. For a 100-icon grid, you simply need the percentage to highlight.
How is an icon array different from a waffle chart?+
Both an icon array and a waffle chart can look similar at first glance, but they answer different questions. Reach for an icon array when the comparisons and patterns it was designed to reveal match what you need to communicate, and choose a waffle chart when its particular strengths better fit your data and audience.
What is another name for an icon array?+
Icon Array is also known as Pictographic array, unit chart, isotype grid. The name varies between fields, but the visualisation technique is the same.
What size of dataset works best for an icon array?+
Icon Array works best for Risk communication, health data, proportions. Outside that range the chart either looks empty or becomes too cluttered to read clearly.
Are icon arrays accessible to screen readers?+
Yes — a icon array can be made accessible to screen readers by pairing it with a clear text summary of the key insight, ensuring color choices meet WCAG contrast guidelines, adding descriptive alt text or aria-label to the SVG, and offering the underlying data as an HTML table fallback for assistive technologies.