A comparison of the effects of data-ink ratio on performance with dynamic displays in a monitoring task

This study investigated the applicability of recommendations for the design of graphs to the design of dynamic graphic displays. Specifically, recommendations regarding the level of data-ink ratio (the ratio of ink showing data to the total ink) were tested. Participants monitored dynamic process control variables in one of three display conditions corresponding to high, medium, and low data-ink ratios. Speed of response to out-of-range variables and level of situation awareness were measured, and aspects of subjective mental workload were assessed. Results indicated some support for principles of non-data-ink reduction: reaction times to out-of-range events were fastest for the highest data-ink ratio condition. Reaction times were similar for the low and medium data-ink conditions, perhaps because these conditions relied on the same graphical specifier. Level of situation awareness showed no effect of data-ink ratio; however, participants appeared to have better awareness of variables, which changed more frequently. Relevance to industry: Increased capabilities and decreased costs of computer displays have increased the likelihood that such technology will be applied in an industrial context. This study suggests that while there may be some applicability of available design guidelines for static graphics to dynamic displays, a simple translation of the guidelines from a static to dynamic environment is not a guarantee for improved performance.