Discussion
GIST
Not everyone benefits from graphical representations of statistical information, and for some people, numerical representations are actually better suited to foster knowledge.We were first asking which representation gets chosen more often and whether people chose representations in line with underlying skills, particularly graph literacy, but also numeracy. In line with previous research, most participants chose the graphical over the numerical representation (e.g., Nayak et al.Our second question was whether allowing people to choose the representation would yield better objective comprehension and recall of the information, which could be the case if choice fosters the match between people’s abilities and chosen representations. Our results, however, show that choosing does not increase comprehension and recall overall. To test whether this null effect could be attributed to limited power to detect a significant effect, we ran a simulation-based sensitivity analysis following DeBruine and BarrWith regard to different types of knowledge, choice did not affect gist knowledge and recall at all, yet it slightly increased verbatim knowledge compared with the “no choice” condition. However, although this increase in verbatim knowledge was statistically significant, it is unclear whether this increase of about 5 percentage points on 1 knowledge dimension is clinically relevant given a baseline performance of about 70% (across both points in time). Furthermore, whereas having precise verbatim knowledge about clinical options is clearly important, gist knowledge may in fact matter more for making medical decisions.The third and final question was whether subjective ratings of accessibility and/or attractiveness would be increased in the “choice” condition, revealing potential motifs of choosing a particular representation. In line with the general preference for the graphical representation, attractiveness ratings of the graphical representation were higher than those of the numerical representation. Importantly, choice consistently increased ratings of attractiveness in comparison with the randomly allocated representations, for both numbers and graphs. This suggests that perceptions of how attractive particular representations are for individual participants played an important role when they chose between representations. Of course, there could additionally be an effect in the other direction, that is, from choice to attractiveness. It is very well documented that people judge options to be more desirable after they have chosen them, even if desirability was identical before making the choice.Whereas choice did not generally increase rated accessibility, it specifically increased ratings of accessibility for the graphical representation. Yet this increased accessibility did not translate into increased overall knowledge scores, as summarized above. In fact, when looking at bivariate correlations between ratings of accessibility and the various knowledge scores (gist and verbatim knowledge at T1 and T2, respectively), it turns out that they are, by and large, uncorrelated with one another; in one case, there is even one small negative correlation, indicating lower gist knowledge at T1 with higher ratings of accessibility (To summarize, the choice between a graphical and a numerical representation 1) revealed a general preference for the graphical representation, and this preference was not related to abilities (graph literacy and numeracy, respectively); 2) did not yield better comprehension and recall overall; and 3) was correlated with increased attractiveness ratings for chosen representations compared with their randomly allocated counterparts and for graphs additionally with increased perceived accessibility (without translating into increased knowledge). Taken together, letting patients choose the representation is not an efficient way to ensure they receive a representation that they understand or recall well. Although choice improved verbatim knowledge, this limited benefit is not enough to recommend giving patients the opportunity to choose a representation as an approach to improve knowledge of medical information. Rather, these results suggest that people choose the representation they thought of as more attractive and, at least for graphs, the one they believe to more accessible, rather than choosing the one that they objectively comprehend better.