Fuelling an investigative mindset: the importance of pre-interview planning in police interviews with suspects

Figures & data

Table 1. Means and standard deviations of self-reported interviewer behaviour as measured by a 5-point scale (1 = Hardly ever, 5 = Nearly always).

Interviewer behaviour variable	M (SD)
Preparation
1. Review information	4.37 (0.68)
2. Develop interview plan	4.00 (0.81)
Interviewing practices
1. Clarify inconsistencies	4.26 (0.63)
2. Appear attentive	4.14 (0.65)
3. Ask open-ended questions	4.06 (0.69)
4. Check suspects’ understanding	4.02 (0.69)
5. Build rapport	3.98 (0.79)
6. Explain interview purpose	3.93 (0.80)
7. Repeat questions to check consistency of replies	3.85 (0.80)
8. Present role as finding the truth	3.77 (0.92)
9. Elicit free recall	3.70 (0.86)
10. Attend to basic needs	3.68 (1.01)
11. Offer opportunities to ask questions	3.67 (0.92)
12. Encourage responsibility for action	3.66 (0.86)
13. Tell suspect that telling the truth will make them feel better	3.61 (1.02)
14. Confront with evidence after suspect shared account	3.60 (0.93)
15. Adopt friendly approach	3.53 (0.82)
16. State expectation of truth at start of interview	3.43 (1.09)
17. Remind suspect to cooperate early	3.32 (1.03)
18. Offer verbal encouragement for cooperation	3.30 (1.01)
19. Tell everything	3.24 (1.03)
20. Offer sympathy	3.18 (0.94)
21. Mental reinstatement of context	3.10 (1.00)
22. Remind suspect it is pointless to continue lying	3.08 (1.07)
23. Remind consequences of non-cooperation	3.06 (1.05)
24. Appeal to sense of cooperation	3.04 (1.15)
25. Presenting oneself as being similar	2.98 (1.11)
26. Appeal to sense of right and wrong	2.98 (1.10)
27. Exaggerate strength of evidence	2.94 (1.03)
28. Tell suspect to cooperate and confess early	2.81 (1.11)
29. Point out other peoples’ perception if suspect continues with non-cooperation	2.77 (1.04)
30. Exaggerate offence seriousness	2.62 (1.05)
31. Offer excuses to justify offence	2.49 (1.10)
32. Good cop/bad cop	2.47 (1.04)
33. Confront with evidence before suspect gives account	2.43 (1.13)
34. Raise voice	2.42 (0.92)
35. Interrupt suspects’ denials	2.41 (0.88)
36. Tell suspects I would have done the same	2.31 (1.20)
37. Exaggerate suspects’ concerns	2.30 (1.04)
38. Manipulate self esteem	2.19 (1.06)
39. Allow suspect to control the interview	2.16 (0.99)
40. Express anger/frustration	2.14 (0.91)
41. Minimise suspects’ responsibility for their offences	2.13 (0.98)
42. Suggest incident happened in a certain manner	2.11 (0.95)
43. Downplay seriousness of offence	2.08 (0.96)
44. Blame others for the offence	2.07 (0.97)
45. Self-disclosure to build rapport	2.06 (1.04)
46. Forced choice questions	2.03 (0.95)
47. Rapid fire questioning	1.97 (0.84)
48. Use vulgarities	1.47 (0.82)
Positive interview outcomes
1. Share information on accomplices (where applicable)	3.19 (0.76)
2. Reveal other offences	2.81 (0.93)
3. Confess to offence	3.25 (0.69)
Negative interview outcomes
1. Remain silent	1.78 (0.75)
2. Retract confession	2.00 (0.84)
3. Allege illegal interviewing practices	1.35 (0.68)
4. Allege pressured to confess	1.35 (0.66)

Table 2. Factor loadings, eigenvalues and percentage of accounted variance of interviewing behaviour.

Interviewing behaviour	1	2	3	4
Maximization (α = 0.84)
Remind suspect to cooperate early	0.688
Remind consequences of non-cooperation	0.665
Point out other peoples’ perception if suspect continues with non-cooperation	0.623
Remind suspect it is pointless to continue lying	0.581
Appeal to sense of cooperation	0.548
Tell suspect to cooperate and confess early	0.525
Exaggerate strength of evidence	0.510
Appeal to sense of right and wrong	0.487
Exaggerate suspects’ concerns	0.482
Exaggerate offence seriousness	0.434
Minimization (α = 0.79)
Offer excuses to justify offence		0.647
Minimise suspects’ responsibility for their offences		0.642
Tell suspects I would have done the same		0.64
Blame others for the offence		0.593
Offer sympathy		0.556
Self-disclosure to build rapport		0.538
Downplay seriousness of offence		0.516
Allow suspects to control interview		0.474
Presenting oneself as being similar		0.417
Rapport (α = 0.75)
Explain interview purpose			0.708
Attend to basic needs			0.599
Check suspects’ understanding			0.598
Appear attentive			0.557
Clarify inconsistencies			0.550
Mental reinstatement of context			0.532
Present role as finding the truth			0.524
Offer opportunities to ask questions			0.484
Elicit free recall			0.473
Tell everything			0.451
Intimidation (α = 0.74)
Raise Voice				0.685
Express anger/frustration				0.676
Use vulgarities				0.617
Rapid fire questioning				0.611
Forced-choice questions				0.488
Eigenvalue	7.29	3.65	1.77	1.49
% of explained variance	21.50	10.74	5.22	4.39

Extraction Method: Principal Component Analysis. Rotation Method: Varimax with Kaiser Normalization.

Table 3. Results of regression models predicting interviewing behaviour usage from investigative experience, confidence, duration of interviews, and type of crime.

	B	SE	b	t	p
Preparation: F(8, 566) = 4.37, p < .001, R^2= 0.06
Experience	0.024	0.02	0.054	1.193	0.233
Confidence	0.069	0.021	0.141	3.331	0.001
Duration	0.002	0.001	0.139	2.929	0.004
Type of crime
Interpersonal	−0.15	0.09	−0.085	−1.664	0.097
Property	−0.049	0.067	−0.039	−0.734	0.463
Commercial	0.029	0.099	0.015	0.299	0.765
Cybercrime	−0.232	0.173	−0.057	−1.339	0.181
Others	−0.05	0.129	−0.018	−0.39	0.697
Component 1 (Maximization): F(8, 566) = 0.94, p = 0.486, R^2 = 0.01
Experience	−0.018	0.023	−0.037	−0.794	0.428
Confidence	0.03	0.023	0.057	1.313	0.19
Duration	0.002	0.001	0.086	1.772	0.077
Type of crime
Interpersonal	−0.174	0.1	−0.09	−1.732	0.084
Property	−0.039	0.074	−0.029	−0.53	0.597
Commercial	−0.085	0.11	−0.039	−0.778	0.437
Cybercrime	−0.02	0.193	−0.005	−0.105	0.917
Others	−0.209	0.144	−0.068	−1.457	0.146
Component 2 (Minimization): F(8, 566) = 0.55, p = 0.817, R^2 = 0.01
Experience	0.031	0.021	0.069	1.47	0.142
Confidence	−0.002	0.021	−0.004	−0.089	0.929
Duration	0	0.001	−0.018	−0.37	0.711
Type of crime
Interpersonal	−0.078	0.093	−0.044	−0.84	0.401
Property	−0.018	0.069	−0.014	−0.264	0.792
Commercial	−0.061	0.102	−0.03	−0.593	0.553
Cybercrime	−0.116	0.179	−0.028	−0.644	0.52
Others	−0.191	0.133	−0.067	−1.435	0.152
Component 3 (Rapport): F(8, 566) = 7.42, p < 0.001 R^2 = 0.10
Experience	0.04	0.015	0.119	2.675	0.008
Confidence	0.042	0.015	0.115	2.754	0.006
Duration	0.002	0.001	0.149	3.204	0.001
Type of crime
Interpersonal	−0.037	0.066	−0.028	−0.555	0.579
Property	−0.123	0.049	−0.129	−2.496	0.013
Commercial	−0.033	0.073	−0.022	−0.453	0.65
Cybercrime	−0.15	0.128	−0.049	−1.171	0.242
Others	−0.088	0.095	−0.042	−0.928	0.354
Component 4 (Intimidation): F(8, 566) = 0.81, p = 0.594, R^2 = 0.01
Experience	0.009	0.02	0.019	0.418	0.676
Confidence	−0.008	0.021	−0.016	−0.36	0.719
Duration	0.001	0.001	0.058	1.191	0.234
Type of crime
Interpersonal	−0.149	0.091	−0.086	−1.639	0.102
Property	−0.045	0.067	−0.036	−0.664	0.507
Commercial	−0.114	0.099	−0.057	−1.143	0.253
Cybercrime	0.186	0.175	0.046	1.062	0.289
Others	−0.127	0.13	−0.046	−0.976	0.33

Table 4. Correlations between the main interviewing behaviour variables.

Variable	2	3	4	5	6	7
1. Preparation	0.009	0.011	.382**	−0.04	.116**	0.014
2. Maximization		.617**	.171**	.526**	0.028	.098*
3. Minimization			.178**	.451**	.116**	.218**
4. Rapport				−0.058	.175**	−0.062
5. Intimidation					0.018	.277**
6. Positive outcomes						−0.046
7. Negative outcomes						-

*p < .05; **p < 0.1.

Data availability statement

Data is unavailable. The organization who provided the authors access to the data for the purpose of the current study did not agree for the raw dataset to be made available publicly.