Verdict spotting: investigating the effects of juror bias, evidence anchors and verdict system in jurors

Figures & data

Figure 1. Visual analogue scale measuring the belief in guilt score.

Figure 2. Line plots of average guilt scores at Timepoints 1 to 11 for weak-first (dashed line) and strong-first (solid line) evidence anchor condition. The corresponding shaded areas denote ±1 SE around the mean.

Table 1. Minimum and maximum scores for each of the constructs within the PJAQ.

PJAQ construct	Minimum score	Maximum score
Racial bias	4	20
Innate criminality	4	20
Social injustice	4	20
Cynicism towards the defence	7	35
System confidence	6	30
Conviction proneness	5	25
Total	30	150

Note: PJAQ = Pre-trial Juror Attitude Questionnaire.

Table 2. Descriptive statistics for each of the constructs within the PJAQ.

PJAQ construct	M	SD
Racial bias	8.57	2.12
Innate criminality	7.53	2.16
Social justice	12.58	2.30
Cynicism toward the defence	20.16	3.69
System confidence	15.32	3.16
Conviction proneness	13.99	3.23

Note: PJAQ = Pre-trial Juror Attitude Questionnaire; M = Mean; SD = Standard Deviation.

Table 3. Final belief of guilt scores grouped by evidence anchor and vignette.

Factor	Final belief of guilt score (0–14)
	M (SD)	Minimum	Maximum
Anchor
Weak-first	7.05 (3.44)	0	13.8
Strong-first	6.7 (3.16)	0.15	13.4
Vignette
Vignette 1	7.83 (3.49)	0.25	13.8
Vignette 2	6.37 (3.03)	0	12.6

Table 4. Verdict frequency within the evidence anchor, verdict systems and vignette predictor variables.

Factor	Verdict frequency
	Guilty	Not guilty	Not proven
Anchor
Weak-first	41	50	37
Strong-first	27	58	43
Verdict system
Two	42	86	N/A
Three	26	22	80
Vignette
Vignette 1	41	50	37
Vignette 2	27	58	43