Strategies for Detecting Difference in Map Line-Up Tasks

The line-up task hides a plot of real data amongst decoys built around some plausible null hypothesis. It has been proposed as mechanism for lending greater reliability and confidence to statistical inferences made from graphics. proposition is seductive one, but whether or not line-ups guarantee consistent interpretation structure an open question, especially when applied representations geo-spatial data. We build on empirical work the extent which can be reliably judged in map line-ups, paying particular attention strategies employed making judgements. conducted in-depth experiments with 19 graduate students equipped moderate background geovisualization. consisted series tasks two designs: choropleth maps centroid-dot alternative. chose challenging hope exposing participants’ sensemaking activities. Through structured qualitative analysis think-aloud protocols, we identify six evaluate their effects judgements line-ups. find five applicable most visualization types, one that seems designs. could single successful strategy, users adopt mix different strategies, depending circumstances. also found were easier use than maps.