The assumption that training and assessment increases NTSs is reasonable based on documented experience [28, 29, 37, 38] and relevant literature [6, 11, 24, 25, 30]. However, direct evidence of improved outcomes or reduced amount of errors as results of training in and assessment of NTSs is sparse in the prehospital domain. The results of this study must be evaluated in respect to the lack of such evidence. The results are also hampered by the low response rate, which makes it ambitious to make strong conclusions. Nevertheless, the tendencies of frequently more training in and assessment of NTSs in HEMS than for GEMS, and that simulation-based training appears to be more frequent than assessment for both the EMSs, are unambiguous.
Comparison of HEMS and GEMS
The physical environment and task-related differences between HEMS and GEMS may demand different levels of training in NTSs. However, the fact that both prehospital services perform safety-critical operations with a low tolerance of error implies a need for training . One appealing reason for the observed variation in training is the safety culture. NTSs and CRM have been essential features in preventing errors in the aviation industry for a long time . The acknowledgement of human limitations has promoted the need to invest resources in training in NTSs . There is a lack of such strong traditions in GEMS , when compared with HEMS, and this may be an explanation of the observed results. Some of the aviation-related tasks performed in HEMS are claimed to be more procedure-based, thus simplifying the simulations and assessments . Training on the base may also be easier to conduct for HEMS than for GEMS, due to the dynamics of the working environment .
Lack of assessment
In both HEMS and GEMS, our findings show a tendency of less assessment of NTSs than simulation-based training. Just as the effect of simulation-based training should not be underestimated , neither should the effect of assessment. Incorrect behaviour, which is not detected, induces the likelihood of errors that could have been prevented . Many of the tasks executed in the EMS are routines, which need to be corrected if they are wrong. Frameworks and tools exist to assess the NTSs in medical teams [37, 40]. However, none are custom-made for the prehospital environment . Proper training without any feedback from qualified personnel can limit the value and learning . In addition to maximize training outcomes, systematic assessment of the NTSs (i.e. debriefing) may detect CRM issues and improve the simulation-based training .
The greater and lesser focus in the Norwegian HEMS and GEMS
Within both EMSs, the frequency of training in and assessment of teamwork appears to be greater than that of the other NTSs. Strong teamwork is considered fundamental to patient safety and thus, not surprisingly, a major focus, independent of profession and EMS . Each member of an EMS team needs to be aware of his/her own and the other team members’ roles and tasks, to ensure effective and safe patient care, as the safety in the EMS domain relies on mutual understanding among the team members .
Our data indicate that less training in and assessment of coping with fatigue, compared to the other NTSs, is present in both HEMS and GEMS, which was also observed in HEMS during 2011 . The previous study , reflected on coping with fatigue as not being an explicit NTS category per se but rather an influencer affecting the other NTSs. This study supports such an argument. Fatigue, which is common in the EMS environment , ultimately threatens the other NTSs , such as teamwork . Therefore, the post-assessment of simulations that comprise fatigue is important, to exploit the full potential of the simulations.
Comparison of the health trust and flight operator
Compared with flight operator employees, i.e. pilots and HCMs, our data indicate that personnel in the health trust undergo training and assessment significantly less frequently. A possible explanation is the difference in safety culture, as already mentioned. However, a strong safety culture is not a persistent quality that a group achieves automatically. It is a result of focus, resources and commitment over time. In the Norwegian HEMS, significant amounts of resources have been allocated in recent years to enhance training and NTSs . Daily clinical duties in the health trust appear to be less suitable for simulation-based training , as it will be too time-consuming and costly, hampering the amount of CRM interventions. However, in situ simulation-based training during on-call hours in the Norwegian HEMS has proven to be feasible . Future research may address the possibility for the health trust to learn from HEMS and adopt similar interventions in their daily duties.
The greater frequency of training in and assessment of NTSs observed among flight operator employees, compared to health trust employees, is no surprise. This tendency was also identified in the study from 2011 . Major disincentives of performing simulation-based training are associated with time-consumption, interruption of daily duties and increased overall expenses . Standards that specify requirements of training may inhibit these natural disincentives, and promote participation in training among the EMS personnel.
In the Norwegian HEMS, standards related to the competency of each profession (i.e. pilot, HCM , anaesthesiologist ) are established. Within these standards, regular interdisciplinary training is emphasised to achieve high quality health care . The standards are perceived as guiding norms , that intend to ensure adequate skills among the personnel in the Norwegian HEMS. In the Norwegian GEMS, basic requirements related to education and skills of each profession are also established , but without any further specifications on training, frequency of training, and development of the necessary prehospital skills of GEMS personnel. We call for more research related to establishing such standards in GEMS, which can be motivated by the ones in HEMS.
Comparison of health trust employees
Among the health trust employees, physicians appear to undergo the greatest amount of training in and assessment of NTSs. The intuitive explanation is the close relationship these physicians have to the aviation safety culture through their experience from HEMS. Although the anaesthesiologists are not obligated to participate in the training conducted in HEMS, which is mandatory for the pilots and HCMs, it is strongly recommended. Opportunities to participate in training and being a member of a culture with a focus on NTSs may have induced an awareness of training and assessment among the physicians.
Equal backgrounds and similarities in responsibility may hamper the development and learning within the team. Diversity in a team can raise awareness of differences and has a positive effect on learning [51, 52]. For GEMS, it can be beneficial to establish a closer relationship with HEMS, with respect to training, in order to promote awareness of their own capabilities and NTSs.
There is an ongoing debate in the Norwegian prehospital domain regarding EMT apprentices conducting on-the-job practice (following the first draft of the Norwegian prehospital emergency medicine regulation ), as they are still pursuing their licence. If NTSs are considered to be one of the vaguely stated “required qualities” in the Norwegian prehospital emergency medicine regulation for EMS personnel , we may question whether EMT apprentices are eligible to participate in emergency missions. The frequency of training in and assessment of NTSs for EMT apprentices indicates a substantial lack of focus on NTSs and CRM interventions in their education. Our data imply a potential for improvement of simulation-based training in and assessment of NTSs among the EMT apprentices, which the educational programmes in Norway need to be aware of.
An opportunity for GEMS
There has been an increasing focus on the importance of NTSs and simulations to ensure safety within the Norwegian HEMS over recent years. Specific initiatives have been launched to increase the frequency of training in and assessment of NTSs. In 2011, the Norwegian air ambulance foundation established Camp Torpomoen , which is an intensive training programme, in which pilots, HCMs and anaesthesiologists practise together on rare and challenging tasks in safe environments. Another NTS-related initiative in HEMS is the Fatigue Risk Management Programme, initiated in 2013, with the purpose of documenting the physical impact of the working environment and sleep deprivation.
Interestingly, our data imply that the frequency of simulation-based training and assessment observed in HEMS during 2011  is statistically insignificantly different from the frequency observed in GEMS during 2015 (Fig. 4 and Table 4), except for the cases of communication and coping with fatigue. The tendency is that GEMS underwent both training and assessment more frequently during 2015 than HEMS did in 2011. Before the great NTSs-offensive in the Norwegian HEMS, the data indicate that there was no particular association between working in either HEMS or GEMS and the frequency of simulation-based training in and assessment of NTSs. Based on this study, there are now reasons to think otherwise. The potential for learning across the EMSs appears to be present, and it may be a great opportunity for GEMS to gain experience from HEMS. However, the practice applied in HEMS should be adjusted to better fit the GEMS environment, as simulations need to be specifically designed to incorporate significant differences across the two domains [6, 20].
Limitations and strengths of the study
The response rate among HEMS employees was substantially lower than for the previous study in 2011. This calls into question the representativeness of the 2015 HEMS population. Only one fourth of the GEMS population was included in this study. It is ambitious not to consider non-respondents bias having an impact on the results. However, the observed trends are consistent and unambiguous.
The number of respondents who answered “Other” about their profession, due to having achieved/executing more than one, was significant (n = 63). Respondents with “Other” as a profession were categorized manually based on specifications in a free text answer. We had also omitted “EMT apprentice” in the predefined professions in the questionnaire. 24 respondents wrote “EMT apprentice” (“Ambulanselærling”) in a free text field, which we manually categorized as a unique group.
Comparing professions in HEMS and GEMS involves a challenge in sample sizes. It is reasonable to believe that the smaller sub-populations, e.g. pilots, have affected the significance of some results. On the other hand, non-parametric statistical tests, such as the Fisher’s exact test and odds ratio, are resilient to different sample size, strengthening our results.
Dichotomizing the question items into no training/assessment and some training/assessment, reduced the possibility of over- or underreporting, due to respondents not remembering how many times they actually underwent training or assessment.
The questionnaire was tested on a group of seven prehospital healthcare workers to ensure correct terminology. We assumed that all the respondents understood the questions, as no additional explanations and definitions were provided. HEMS employees are more familiar with CRM training and may have better understood what the questions were referring to. The possibility that respondents did not report truthfully is also present.
A weakness of the study, which was not the intention, is the possibility of making strong conclusions regarding the quality of NTSs among the EMSs in Norway. Ultimately, it is the quality, and not the frequency of training and assessment, of the NTSs that the individuals possess which is important.