Trend target: 12, Cluster target: 5 
Trend target: 12, Cluster target: 5 
Participant Responses

Trend target: 12, Cluster target: 5 
Participant Responses

Parameters  
$\sigma_T$: Variability in $y$  $\lambda$: Mixing parameter  $K$: # clusters 
$\sigma_C$: Variability around cluster centers  
Trend Emphasis  
Strength  0  1  2  
Cluster Emphasis 
0  Plain  Line  Line + Pred. Interval 
1  Color Shape 
Color + Line  
2  Color + Shape Color + Ellipse 
Color + Ellipse + Line + Pred. Interval 

3  Color + Shape + Ellipse 
Palettes selected to provide maximum perceptual distance (Ç. Demiralp, et al., 2014).
Shapes conform to guidelines in Robinson (2003) and Lewandowsky & Spence (1989).
Model Parameters

Plot Level

Plot Aesthetics

Evaluation Level

1201
participants provided: 12010
total)
Participants selected more cluster targets than line targets.
5 plot types were expected to emphasize clustering; only 2 plot types were expected to emphasize trends.
Define $C_{ijk}$ to be the event
{Participant $k$ selects the
cluster target for dataset $j$
with aesthetic set $i$},
and $T_{ijk}$ to be the analogous selection of the trend target.
$$\text{logit }P(C_{ijk}C_{ijk}\cup T_{ijk}) = \textbf{W}\alpha + \textbf{X}\beta + \textbf{J}\gamma + \textbf{K}\eta$$Given that participants identified one of the two target plots...
$\alpha$  data model fixed effects 
$\beta$  effect of specific plot types 
$\gamma_j \overset{iid}{\sim} N\left(0, \sigma^2_{\text{dataset}}\right)$  Dataset random effects 
$\eta_k \overset{iid}{\sim} N\left(0, \sigma^2_{\text{participant}}\right)$  Participant random effects 
$\epsilon_{ijk} \overset{iid}{\sim} N\left(0, \sigma^2_e\right)$  Individual evaluation errors 
Dataset and participant effects are orthogonal by design
Plot types are significantly different if they do not share a letter
Participants are 
Participants are 
Neither Target (N=127)  Cluster Target (N=712)  Trend Target (N=355) 
Neither Target (N=159)  Cluster Target (N=694)  Trend Target (N=333) 
Neither Target (N=188)  Cluster Target (N=715)  Trend Target (N=292) 
Neither Target (N=347)  Cluster Target (N=621)  Trend Target (N=222) 
Trend target: 12, Cluster target: 5 
Participant Responses
