Arrange highlighted figures as a contiguous block for fast proportion reading

Group the highlighted figures into one contiguous block when viewers need a quick percentage read from an icon array. For example, line the colored figures up along one edge or in one corner instead of scattering the same count randomly across the grid.

A contiguous block makes the part-whole relationship visible as one area. A scattered arrangement forces viewers to mentally sum many separated marks, which increases first-glance overestimation and person-to-person variability.

Mechanism: Contiguous grouping reduces the amount of mental aggregation needed to judge the share of highlighted figures.

Evidence: Under a 10-second deadline, random arrangements produced higher mean estimates and wider variability than sequential block arrangements for most tested proportions, and the mixed model found a 10% increase in relative inaccuracy for random layouts (Ancker et al., 2011).

Notes: The difference between random and sequential arrangements was not clearly present for the tested proportions near 40% to 50%.

• User Goal: Communicate the size of one proportion quickly.
• Task: Estimate a percentage from the figure itself rather than by counting.
• Data: One part-whole proportion shown in an icon array.
• Chart Setting: Unlabeled display, brief viewing, and a design that relies on first impressions.
• Audience: Consumers or patients with mixed numeracy and education levels.
• Success Criterion: Viewers give fast estimates that are closer to the true proportion and less variable across people.

Break it when: The depicted proportion is around the tested midrange near 40% to 50% under the same brief-viewing conditions. Why: In this study, random and sequential arrangements did not show a clear accuracy difference in that range.

Sacrifice: The display gives up a visually scattered look. Risk: A contiguous block does not make estimates exact; even sequential high-percentage arrays were still overestimated. Mitigation: Use the block arrangement when fast visual accuracy matters more than showing a scattered pattern.

Mistake: Keep the highlighted figures scattered because the average estimate looks roughly close to the true percentage. Why it fails: Random layouts still produced larger overestimates and much wider variation across viewers.

Failure Sign: Viewers’ first guesses are higher or more spread out when the same percentage is shown as a scatter instead of a block. Quick Check: Show blocked and random versions of the same array for about 10 seconds and compare the guesses. Stronger Test: Choose the arrangement that yields the smaller spread of estimates across viewers.

• Move the highlighted figures so they touch and form one continuous block.
• Place that block along one edge or in one corner of the icon array.
• Keep the number of highlighted figures constant while changing only the arrangement.