Table 3.

Probabilities entered into the decision analytic model

Event point	Probabilities	Source
Usual response (‘before’ arm)
Section 136 detention in custody	0.33	Data and assumption 1
Section 136 detention in hospital	0.21	Data and assumption 1
No further action	0.46	Assumption 1
Street triage (‘after’ arm)
Proportion of time street triage available	0.65	Assumption 2
Proportion of time street triage unavailable	0.35	Assumption 2
Response when street triage available
Referral	0.94	Data
Section 136 detention in custody	0.02	Data
Section 136 detention in hospital	0.01	Data
No further action*	0.03	Data
Services street triage refer to:†
GP	0.58	Data
Mental health service	0.05	Data
A&E	0.15	Data
Other community service	0.15	Data
Informal referral to hospital	0.06	Data
Response during periods when street triage not available
Section 136 detention in custody	0.41	Data and assumption 1
Section 136 detention in hospital	0.48	Data and assumption 1
No further action	0.11	Assumption 3
Assumptions 1. Assumes the total number of incidents in the usual response arm is the same as the total number of incidents in the street triage arm (n=358). 2. Assumes 65% of incidents take place during street triage hours thus 35% take place when street triage is unavailable (street triage n=233, thus n=125 take place when street triage unavailable). 3. Total incidents when street triage unavailable (n=125, as per assumption 2) minus total number of section 136 detentions (n=111), giving total number of no further action (n=14), which is 11% of total incidents.

Some sets of probabilities do not add up to 1 due to rounding.

*Includes follow-up with family.

†Excludes unknown and arrest.

GP, general practitioner.