Re-examining the dual harm profile: an assessment using US prison population-level data

Figures & data

Table 1. Prevalence rates and group characteristics.

Group	n	Prevalence (%)	Female (%)	Age at admittance M (SD)	Ethnicity (Ethic minority %)	Married (incl. common law) (%)	Sentence length [Years, (SD)]
No Harm	20,413	89.1	7.0	31.2 (10.0)	66.1	27.3	100.1 (280.5)
Other-harm	1,984	8.7	4.8	25.9 (8.3)	83.1	17.3	82.8 (251.6)
Self-harm	325	1.4	7.4	25.8 (7.4)	52.6	23.1	66.6 (226.7)
Dual Harm	196	0.9	7.7	23.7 (7.2)	71.4	14.8	72.2 (229.7)
Full sample	22,918	100.0	6.8	30.6 (10.0)	67.6	26.2	97.9 (277.1)

Figure 1. Annual incident disciplinary events rate (excluding violence and self-harm) by group.

Table 2. Rate ratios for pairwise comparisons in annual incident rate between groups (with p adjusted for multiple comparisons).

Contrast	Rate ratio	95% CI	Adjusted p
Dual Harm – No Harm	5.70	4.90, 6.63	<.0001
Dual Harm – OH	1.73	1.48, 2.03	<.0001
Dual Harm – SH	1.43	1.15, 1.77	<.01
OH – No Harm	3.29	3.06, 3.55	<.0001
SH – No Harm	3.99	3.39, 4.69	<.0001
OH – SH	0.83	0.70, 0.98	<.05

Table 3. Odds ratios and 95% CIs for the differences for each of the 11 disciplinary categories.

Category	Dual Harm – Other-harm	Dual Harm – Self-harm	Dual Harm-No Harm	Other-harm – Self-harm	Other-harm-No Harm	Self-harm-No Harm
Violence-related
Damage	3.90 [2.83, 5.37]***	3.16 [2.07, 4.82]***	20.23 [14.93, 27.40]***	0.81 [0.58, 1.13]	5.18 [4.43, 6.07]***	6.40 [4.67, 8.78]***
Disorder	2.10 [1.45, 3.05]***	2.64 [1.58, 4.42]***	10.69 [7.49, 15.27]***	1.26 [0.84, 1.89]	5.09 [4.31, 6.01]***	4.05 [2.73, 5.99]***
Refusal or Failure	1.55 [1.15, 2.07]*	1.52 [1.06, 2.17]*	6.52 [4.91, 8.65]***	0.98 [0.77, 1.25]	4.22 [3.82, 4.65]***	4.30 [3.43, 5.37]***
Interpersonal Misconduct	1.88 [1.35, 2.63]***	1.69 [1.11, 2.57]*	6.36 [4.62, 8.76]***	0.90 [0.66, 1.22]	3.38 [2.96, 3.86]***	3.77 [2.82, 5.03]***
Sexual Misconduct	2.22 [1.65, 2.99]***	2.68 [1.86, 3.88]***	12.63 [9.49, 16.82]***	1.21 [0.94, 1.56]	5.68 [5.12, 6.31]***	4.71 [3.70, 5.99]***
Sexual Violence	2.78 [1.71, 4.51]***	2.91 [1.46, 5.80]**	17.08 [10.75, 27.14]***	1.05 [0.59, 1.86]	6.14 [4.72, 8.00]***	5.87 [3.36, 10.27]***
Threats of Violence	3.88 [2.85, 5.30]***	4.06 [2.78, 5.92]***	25.92 [19.18, 35.03]***	1.04 [0.81, 1.35]	6.68 [5.99, 7.44]***	6.39 [5.02, 8.14]***
Substance-related
Substance Use	0.67 [0.46, 0.98]	0.71 [0.45, 1.11]	1.40 [0.97, 2.02]	1.06 [0.80, 1.41]	2.09 [1.87, 2.33]***	1.97 [1.51, 2.56]***
Other non-violent
Unauthorised Possession	1.41 [1.03, 1.93]	1.03 [0.71, 1.51]	3.04 [2.25, 4.10]***	0.73 [0.57, 0.94]*	2.16 [1.93, 2.40]***	2.95 [2.32, 3.74]***
Interference	1.09 [0.69, 1.70]	1.09 [0.63, 1.87]	2.69 [1.75, 4.15]***	1.00 [0.69, 1.44]	2.48 [2.13, 2.88]***	2.48 [1.76, 3.50]***
In place without permission	0.86 [0.59, 1.26]	1.04 [0.66, 1.65]	2.59 [1.80, 3.73]***	1.20 [0.89, 1.63]	2.99 [2.66, 3.38]***	2.49 [1.87, 3.33]***

*p < .05 ** p < .01; *** p < .001

Table 4. Education and health history.

	Variable	No Harm	Self-harm	Other-harm	Dual Harm	Total
Educational	Reading Score (Admission), M (SD)***	8.25 (3.94)	8.00 (3.93)	7.76 (3.78)	7.10 (3.86)	8.20 (3.93)
	Current Education Level, M (SD)***	10.49 (2.03)	10.07(1.80)	10.19 (1.83)	9.79 (1.99)	10.5 (2.02)
	High School Diploma/GED (%)***	41.8	30.15	29.99	22.96	40.45
Health	Drug Dependent (%)	42.04	43.69	39.52	41.33	41.84
	Mental Health (%)***	9.48	39.38	14.82	57.14	10.78

*p < .05 ** p < .01; *** p < .001.

Table 5. Post-hoc contrasts and Hochberg adjusted significance levels (continuous variables).

Variable	No Harm	Self-harm	Other-harm	Dual Harm
High School Diploma/GED	11.88***	−3.81***	−9.94***	−5.01***
Married (incl. Common Law)	10.16***	−1.30	−9.53***	−3.65***
Mental Health	−18.02***	16.75***	6.07***	21.02***

*p < .05 ** p < .01; *** p < .001.

Table 6. Adjusted Standardised Residuals and Hochberg adjusted significance level (categorical variables).

Contrast	Age at Admittance	Current Education Level	Reading Score (Admission)
Dual Harm – OH	−2.14 [−3.58, −0.70]*	−0.40 [−0.70, −0.10]*	−0.65 [−1.23, −0.08]
Dual Harm – SH	−2.09 [−3.83, −0.35]*	−0.28 [−0.64, 0.08]	−0.90 [−1.60, −0.20]*
Dual Harm – No Harm	−7.43 [−8.81, −6.05]***	−0.70 [−0.98, −0.42]***	−1.15 [−1.70, −0.60]***
OH – SH	0.06 [−1.09, 1.21]	0.12 [−0.12, 0.36]	−0.25 [−0.71, 0.22]
OH – No Harm	−5.29 [−5.74, −4.84]***	−0.30 [−0.39, −0.21]***	−0.50 [−0.68, −0.31]***
SH – No Harm	−5.34 [−6.42, −4.27]***	−0.42 [−0.64, −0.20]***	−0.25 [−0.68, 0.18]

*p < .05 ** p < .01; *** p < .001.