Table 1.

Suggested adjustments of the instrument

Component	Basis for change	Description of change
Interpretation of the term ‘hospital level’	The dimensions in the HSOPSC are divided into three ‘hospital’ level dimensions and seven ‘unit’ level dimensions. The dimensions ‘handoffs and transitions’ and ‘teamwork across units’ are related to a system of different prehospital units, which, for this context, are better understood as ‘the prehospital chain’.	No change; we find this acceptable, as the intended ‘hospital’ level may be understood as ‘organizational’ level [35], different from the ‘local unit’ level.
Interpretation of the term ‘unit’	To clarify whether the unit should be understood as the local hospital, the local station/base or the working crew.	The term ‘unit’ was substituted with the term ‘local unit’, and ‘local unit’ is explained as ‘localized at same geographic place’.
Interpretation of the term ‘shift changes’ in item H11a	The term is related to the in-hospital challenge of transferring responsibility for the patient from one care team to another, which is similar to the transfer of the patient between units in the prehospital chain (e.g. between an ambulance and the hospital).	The term ‘shift changes’ was substituted with ‘patient handover’.
Interpretation of idioms in items A14a, C3a and H3a	It is embedded in prehospital professions to take ‘shortcuts’ in emergency dispatch situations and work in ‘crisis mode’ at the action site. Also, the expression ‘fall between the cracks’ may be difficult to understand in the context of the prehospital chain.	A minor explanation/example was amended to each of the idioms in the questionnaire.
Interpretation of item A5	The item ‘staff in this local unit work longer hours than is best for patient care’, is challenging due regulation by the Working Environment Act [65] and not by the EMS management.	No change; the item is trying to capture a facet of the dimension ‘staffing’ and its influence on patient safety, independent of practical underlying causes; i.e. the results may indicate a weakness in the regulations.
Interpretation of items A11 and H2	The items A11 ‘when one area in this unit gets really busy, others help out’, and H2 ‘units in the prehospital chain do not coordinate well with each other’ were both deemed difficult to interpret in a prehospital context. An emergency dispatcher provides and coordinates the assignments for different vehicles, which is not similar to hospital situations where personnel can move and coordinate more freely between units.	No change; this is arguably of little direct relevance for patient safety but relevant for the latent factor ‘teamwork within units’. Emergencies may also exist, where it is possible to offer assistance between vehicles, even if this is not the norm.

Note: ^aThe items in full text are found in Table 6