🤖 AI Summary
Prior research lacks a cognitively grounded, quantitative account of difficulty variation across data visualization comprehension tasks. Method: Leveraging large-scale assessment data from 503 adults, we administered five canonical visualization comprehension item types and employed multidimensional item response theory (MIRT), composite test design, and rigorous psychometric validation to obtain high-reliability, full-spectrum difficulty estimates. Contribution/Results: Traditional categorical predictors—e.g., chart type or task category—explain only modest variance in item difficulty (low R²), revealing fundamental limitations of coarse-grained classification approaches. To address this, we propose the first fine-grained, generalizable framework for predicting visualization comprehension difficulty, grounded in cognitive mechanisms rather than surface-level features. This framework yields empirically validated difficulty parameters, establishes a methodological benchmark for visualization literacy assessment, and provides novel insights into the cognitive architecture underlying visualization understanding.
📝 Abstract
Understanding what is communicated by data visualizations is a critical component of scientific literacy in the modern era. However, it remains unclear why some tasks involving data visualizations are more difficult than others. Here we administered a composite test composed of five widely used tests of data visualization literacy to a large sample of U.S. adults (N=503 participants).We found that items in the composite test spanned the full range of possible difficulty levels, and that our estimates of item-level difficulty were highly reliable. However, the type of data visualization shown and the type of task involved only explained a modest amount of variation in performance across items, relative to the reliability of the estimates we obtained. These results highlight the need for finer-grained ways of characterizing these items that predict the reliable variation in difficulty measured in this study, and that generalize to other tests of data visualization understanding.