Outcome proportions, numeracy, and attribute‐framing bias

Figures & data

Table 1. Mean response indices of the three outcome proportions as a function of framing and numeracy group (Experiment 1; N = 139)

	Proportion	10% or 90%		25% or 75%		40% or 60%
Numeracy	Framing	Mean	SD	Mean	SD	Mean	SD
Low	Positive (90%; 75%; 60%)	5.64	0.97	5.48	0.88	4.90	0.98
	Negative (10%; 25%; 40%)	4.86	1.15	4.05	1.21	4.08	1.24
	Effect size (d[95% CI])	0.75 [0.25, 1.23]		1.39 [0.86, 1.93]		0.76 [0.26, 1.26]
	t, p (df = 69)	3.10, p = .003		5.77, p < .001		3.09, p = .003
High	Positive (90%; 75%; 60%;)	5.33	0.80	5.23	0.78	4.83	0.93
	Negative (10%; 25%; 40%;)	5.00	1.08	4.49	1.09	4.34	1.30
	Effect size (d[95% CI])	0.34 [−0.15, 0.82]		0.76 [0.25, 1.25]		0.42 [−0.07,0.90]
	t, p (df = 66)	1.39, p = .17		3.07, p = .003		1.72, p = .09

short-legendFigure 1.

Table 2. Mean response indices of the three outcome proportions as a function of framing and numeracy group (Experiment 2; N = 420)

	Proportion	10% or 90%		25% or 75%		40% or 60%
Numeracy	Framing	Mean	SD	Mean	SD	Mean	SD
Low	Positive (90%; 75%; 60%)	6.01	0.73	5.44	0.60	4.25	1.15
	Negative (10%; 25%; 40%)	5.06	1.22	3.83	1.10	3.23	1.13
	Effect size (d[95% CI])	0.96 [0.76, 1.16]		1.86 [1.67, 2.06]		0.91 [0.66, 1.16]
	t, p (df = 73–82)	4.31, p < .001		7.95, p < .001		3.91, p < .001
High	Positive (90%; 75%; 60%)	6.18	0.42	5.21	0.66	3.94	1.00
	Negative (10%; 25%; 40%)	5.22	0.97	4.08	1.18	3.03	0.91
	Effect size (d[95% CI])	1.28 [1.08, 1.47]		1.19 [0.95, 1.42]		0.98 [0.75, 1.21]
	t, p (df = 56–61)	4.74, p < .001		4.61, p < .001		3.69, p < .001

short-legendFigure 2.