Field notes
Comparing small cohorts without false precision
When a class has twelve students, percentage swings look dramatic. Practical rules for fair term-to-term reading.
Small cohorts make percentages twitchy. A twelve-student class that gains two learners above band can look like a dramatic leap; losing two can look like a collapse. Directors need rules of thumb before celebrating or panicking.
We suggest printing headcount next to every percentage, and comparing absolute counts across terms when the class is under fifteen. Color bands should use wider ranges for tiny groups so a single student does not flip the story.
During chart-reading sessions, we practice reading the same sheet twice: once with percentages hidden, once with them visible. Teams quickly see where the percentage view overstates change. That habit carries into Monday meetings long after we leave.
Fair comparisons also mean matching like with like—same placement criteria, similar age bands, and the same assessment window. Mixing intensive holiday camps with regular term cohorts invents false narratives.