Observing strategies of drawing data representations

New methods for the assessment of drawing strategies are examined that focus on the analysis of perceptual chunking. The methods are demonstrated with four diverse participants as they copied a line-graph and a bar-chart. Video recordings of the transcriptions were analysed stroke by stroke. Diverse global drawing strategies were used for the line graph whereas all four participants used a similar approach on the bar-chart, but with local differences. Performance fluency varied substantially, particularly in stimuli viewing frequency. Differences in behaviours can be explained in terms of how they perceptually chunked the stimuli. Sample GOMS models were constructed in order to verify that chunking explains the drawing strategies. The potential of using drawing transcription tasks to assess users’ competence with graphs and charts is discussed.