Mr Barton Maths Podcast #211 Research in Action 28: Considering uncertainty when interpreting educational research with Hugo Lortie-Forgues
Feb 11, 2026
Hugo Lortie-Forgues, senior lecturer in psychology and education who studies mathematical cognition and fractions. He talks about common fraction misconceptions in students and teachers. He explains how intervention effects are measured and how different metrics change perception. He explores communicating uncertainty, why ranges can reduce trust, and practical heuristics for judging study quality.
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Teachers Share Common Fraction Misconceptions
- Hugo Lortie-Forgues found both students and many primary teachers hold the same fraction misconceptions, e.g., expecting 1/4 × 1/4 to be larger than 1/4.
- The study tested primary teachers on basic fraction multiplication and revealed surprising shared errors, suggesting teacher knowledge can transmit misconceptions.
Effect Metric Dramatically Alters Perceived Impact
- The metric used to report intervention effects (months of progress, test points, percentiles) strongly changes teachers' perceptions of effectiveness.
- Hugo's experiments showed 'months of progress' tends to make effects look larger than equivalent point or percentile translations.
Effect Sizes Depend On Context And Noise
- Effect sizes (e.g., 0.2 or 0.4 SD) are hard for practitioners to interpret and depend on study context and noise.
- Small lab studies can yield large effect sizes while noisy classroom trials of the same intervention may show smaller effects.