The effect of response modality on witness statements when using the self-administered interview

Figures & data

Table 1. Misleading PEI items presented in the news report.

Item	Video	News report
Corpse	Man	Woman
Perpetrator’s hair colour	Brown	Blond
Weapon’s colour	Black	Silver
Bag	Plastic	Cloth
Car trunk	Open	Closed
Corpse transported by	Two perpetrators	One of the perpetrators
Perpetrators agree to meet at	School	Coffee shop
Tool for burying the body	Shovel	Hoe

Note: PEI = post-event information.

Table 2. Number of correct units of information recalled, accuracy and time taken to complete the SAI^© according to response modality.

Response modality	Correct information			Accuracy			Time
	M	SD	95% CI	M	SD	95% CI	M	SD	95% CI
Spoken-SAI^©	80.87	24.15	[72.01, 89.73]	.91	.03	[.90, .92]	18.14	5.82	[16.00, 20.27]
Typed-SAI^©	73.26	16.05	[67.37, 79.14]	.90	.04	[.89, .91]	30.49	11.22	[26.37, 34.60]
Total	77.06	20.69	[71.81, 82,32]	.90	.03	[.90, .91]	24.31	10.83	[21.56, 27.06]

Note. SAI^© = Self-Administered Interview; CI = confidence interval.

Table 3. Number of correct units of information recalled, accuracy and misleading PEI recalled according to response modality.

Response modality	Correct information			Accuracy			Misleading PEI
	M	SD	95% CI	M	SD	95% CI	M	SD	95% CI
No-SAI^© (control group)	50.97	17.63	[44.50, 57.44]	.87	.07	[.84, .89]	0.90	1.08	[0.51, 1.30]
Spoken-SAI^©	70.16	21.48	[62.28, 78.04]	.90	.05	[.88, .92]	0.55	0.85	[0.24, 0.86]
Typed-SAI^©	67.10	17.69	[60.61, 73.58]	.88	.05	[.86, .90]	0.58	0.72	[0.32, 0.84]
Total	62.74	20.63	[58.49, 66,99]	.88	.06	[.87, .89]	0.68	0.90	[0.49, 0.86]

Note. PEI = post-event information; SAI^© = Self-Administered Interview; CI = confidence interval.

The number of misleading PEI can range from 0 to 8.

Table 4. Number of new and repeated units of information recalled in the free recall task according to response modality.

	Repeated information								New information
	Correct– correct		Incorrect– correct		Correct– incorrect		Incorrect– incorrect		Correct		Incorrect
	M	SD	M	SD	M	SD	M	SD	M	SD	M	SD
Spoken-SAI^©	54.26	19.52	0.42	0.85	0.81	0.98	4.07	2.22	15.45	6.05	2.65	1.70
Typed-SAI^©	49.87	14.49	0.39	0.72	0.58	0.67	4.36	2.76	16.77	8.05	4.26	3.01
Total	52.07	17.19	0.40	0.78	0.69	0.84	4.21	2.49	16.11	7.10	3.45	2.56

Note. SAI^© = Self-Administered Interview.

Data availability statement

The data that support the findings of this study are openly available in Open Science Framework (OSF) at https://osf.io/c4k38/?view_only=2fbe942049a64071a16fa12bca0ff89c.