Table 4. Summary of findings—quantitative studies.

Authors (year)	Cohort studies: sample size	Surveys: mode of delivery, sample size & response rate	Enough statistical power?	Outcome variable (measure)	Follow-up	Confounders controlled?	Results	Summary
Anshel, Umscheid & Brinthaupt (2013)	EDs n = 9	N/A	No	Perceived stress (PSS), job satisfaction (JS), perceived physical energy (13 item measure created by authors), coping style for acute stress (15 item measure created by authors), fitness testing (upper and lower body muscular strength)	Pre-post study	No control for possible confounders	All participants provided with 12-week membership to local fitness club & assigned personal performance coach. Upper & lower body strength & perceived physical energy significantly higher at post-test. No increase in approach-coping strategies; increase in avoidance-coping strategies, but not statistically significant. Perceived stress was lower at post-test, close to statistical significance. No difference in job satisfaction over time.	The coping skills & fitness programme increased perceived physical energy & body strength, & reduced perceived stress, but had no effect on coping strategies or job satisfaction.
Doerner (1987)	N/A	31 distributed, n = 22. EDs & supervisors 69% response, community service officers 80% response. Distributed at start of each shift	No	State anxiety & trait anxiety (STAI)	None	No control for possible confounders	Male EDs had greater TA & SA than community norms. Female EDs had greater TA than community norms. Most-liked aspects (frequency-based questions): helping people, assisting officers, responding to telephone inquiries, excitement & adventure involved in radio work, variety on the job. Negative aspects (frequency-based questions): understaffing & overload, public disrespect & rudeness	Police EDs show elevated stress scores, but are not pathologically stressed. Police EDs report job satisfaction from the range of tasks they perform, but face organisational barriers that affect efficient working
James & Wright (1991)	N/A	Distributed to 518 employees, 358 returned (69% response rate), postal	Yes	Common stressors identifier (42 item measure, developed by authors)	None	N/A	Four factor structure of common stressors identified (1) Organisational & managerial aspects; (2) New, unfamiliar & difficult duties/uncertainty; (3) Work overload; (4) Interpersonal relations	Key stressful situations include dealing with injured children, underuse of ability & potential, inadequate pay, managerial support & facilities at work. How ambulance staff are treated by other colleagues is an area of severe stress.
Jenkins (1997)	N/A	Total number distributed not reported. n = 68, materials hand delivered to participants who completed at work & returned by post	No	Social support (IQ), acute stress (ADSI) coping with effects of storm (WOC), effects of stress (IES), worst health symptom (health survey, author) general psychological distress (BSI GSI)	None	Completer analysis reported; no control for demographic or other confounders	Mean IES scores comparable to other disaster worker studies for Intrusion & for Avoidance. SS negatively associated with distress. EDs who were at work during storm were not more distressed at 2.5 mths than those who were at home. EDs who received CISD were higher in avoidance at 2.5 mths, but they also had higher estimated uninsured property losses & less social network involvement	Effects of storm on EDs were comparable to other disaster workers. CISD associated with higher avoidance, but cannot rule out effect of property damage. Social support deficits associated with greater distress
Pierce & Lilly (2012)	N/A	Total distributed not reported. n = 171 police tele-communicators, option for either hard-copy or online completion	Yes	Exposure to potentially traumatic events/calls (PTEM). Emotional distress related to worst duty-related event (PDI). PTSD symptoms over last 1 mth (PDS)	None	Demographic variables not checked or controlled for	Participants reported experiencing fear, helplessness or horror in reaction to 32% of different types of calls. Peri-traumatic distress: average score was 2.93, higher than comparator sample of police officers (1.3) & civilians (1.69) (comparator sample from Brunet et al., 2001). PTSD symptoms: 3.5% scored at or above 28 (cut-off for probable, current PTSD). Significant positive correlation between peri-traumatic distress & PTSD symptoms	Peri-traumatic distress was high & positively correlated with PTSD symptoms. Despite tele-communicators being physically distinct from traumatic scene, authors suggest they may not be buffered from development of PTSD symptoms
Shakespeare-Finch, Rees & Armstrong (2014)	N/A	Online survey. 120 surveys distributed. n = 60 (50% response rate). Only 44 participants reported experiencing a trauma, & were treated as a ‘trauma sub-sample’	No	Wellbeing (PWS), post-traumatic stress symptomatology (IES-R) & PTG (PTGI). Possible predictors self-efficacy (NGES), shift-work, being a trained ‘peer support officer’, giving & receiving SS (2-SSS)	None	Demographic variables not checked or controlled for	All EMDs reported high levels of self efficacy, total SS & the giving of SS. Self-efficacy, giving SS & receiving SS positively predicted psychological wellbeing across main sample (n = 60). 44 participants reported experiencing trauma; these 44 EMDs only were examined for predictors of PTSD symptoms & PTG. Shift work & receiving SS negatively predicted PTSD symptoms in trauma subsample. Receiving SS positively predicted PTG in trauma subsample	Self-efficacy & receiving SS positively associated with psychological wellbeing. Receiving SS also related to higher levels of PTG & lower levels of PTSD
Sprigg, Armitage & Hollis (2007)	N/A	Total distributed not reported. n = 48, survey method of delivery not reported	No	No. of verbally abusive calls, emotional exhaustion, health (GHQ), job-related strain & employee turnover intent (other measures not named). Perceived perpetrators of & perceived reasons for verbal abuse	None	Demographic variables not checked or controlled for	7% of calls on average verbally abusive. Patients & emergency callers perceived as greater source of abuse than other professionals. ASCR staff perceived caller frustration & anxiety as most common cause of verbal abuse. Greater no. of abusive calls significantly positively correlated with levels of emotional exhaustion, depersonalisation & anxiety, but not depression & GHQ scores. Organisational commitment not significantly correlated with no. of calls, but significantly negatively correlated with all other outcomes	Call handlers reporting greater no. of abusive calls reported higher levels of emotional exhaustion, depersonalisation, & anxiety, but not depression & GHQ scores. Organisational commitment lower in those experiencing physical & psychological distress
Wastell & Newman (1996)	Total staff n = 45, but not clear if all took part	N/A	Unclear	External work demands (counted no. of simultaneously active jobs handled by ED at time of sampling). HR, BP, anxiety & fatigue (VAS), ED perceptions of ALERT after implementation	Before & after study; approx. 4 mths after implementation of ALERT	Not reported	Improvements in performance with ALERT; ambulances arriving within 8 mins increased from 55.4% to 64.4%. No significant difference between HR & BP between paper based & computer based system, but increased workload demands associated with increase in BP in paper system only. Anxiety & fatigue increased with workload in both systems, but effect greater in paper system. EDs reported reduced stress levels & improvement in service performance using ALERT	Perceived stress reduced & service performance improved following implementation of ALERT
Weibel et al., 2003	EMDs n = 8; controls n = 8. Controls were staff in author’s lab, matched for age, sex & smoking status	N/A	No	Salivary cortisol (sampled every 2hrs, from 9am to 7pm, across 1 day), subjective stress perception, attitude toward work (measures not named)	None	Not reported	Daytime cortisol secretion higher in EMDs than controls. Both groups: cortisol levels decreased towards end of day. Cortisol levels constantly higher in EMDs. Positive correlation between individual total cortisol levels & perceived emotional stress. Poor physical work environment positively associated with poor relationships with hierarchy	EMDs experience higher secretion of cortisol levels compared to lab staff on rest days

Notes.

Abbreviations

ADSI

Acute Disaster Stress Index

ASCR

ambulance service control room

approx.

approximately

BP

blood pressure

BSI GSI

Derogatis Brief Symptom Inventory Global Severity Index

CISD

Critical Incident Stress Debriefing

ED

emergency dispatcher

GHQ

General Health Questionnaire

HR

heart rate

IES

Impact of Events Scale

IES-R

Impact of Events Scale-Revised

IQ

Incident Questionnaire

JS

general job satisfaction measure

mins

minutes

mth

month

NGES

New General Efficacy Scale

no.

number

PDI

Peri-traumatic Distress Inventory

PDS

Post-traumatic Diagnostic Scale

PSS

Perceived Stress Scale

PTEM

Potentially Traumatic Events/calls Measure

PTG

post-traumatic growth

PTGI

Post Traumatic Growth Inventory

PTSD

post-traumatic stress disorder

PWS

Psychological Wellbeing Scale

SA

state anxiety

SS

social support

STAI

State-Trait Anxiety Inventory

TA

trait anxiety

VAS

visual analogue scales

WOC

Ways of Coping Questionnaire

2-SSS

2-way Social Support Scale