VALIDATION OF THE CROATIAN VERSION OF THE SENSE  
OF COHERENCE 29-ITEM SCALE IN CROATIAN NURSES
Martina SMREKAR
1,2
, Lijana ZALETEL-KRAGELJ
3
, Olivera PETRAK
1
, Alenka FRANKO
3,4*
 
1
University of Applied Health Sciences Zagreb, Mlinarska cesta 38, 10000 Zagreb, Croatia 
2
University of Ljubljana, Faculty of Medicine, Zaloska 4, 1000 Ljubljana, Slovenia 
3
University of Ljubljana, Faculty of Medicine, Chair of Public Health, Zaloska 4, 1000 Ljubljana, Slovenia
4
University Medical Centre Ljubljana, Clinical Institute of Occupational Medicine, Poljanski nasip 58, 1000 Ljubljana, Slovenia
Received: Dec 19, 2019
Accepted: May 26, 2020 
Original scientific article
*Corresponding author: Tel. + 386 31 842 308; E-mail: alenka.franko@siol.net
10.2478/sjph-2020-0020 Zdr Varst. 2020;59(3):155-163
155
OVREDNOTENJE HRVAŠKE VERZIJE DOLGEGA VPRAŠALNIKA  
O OBČUTKU KOHERENTNOSTI (SOC-29) PRI MEDICINSKIH SESTRAH
© National Institute of Public Health, Slovenia. 
Smrekar M, Zaletel-Kragelj L, Petrak O, Franko A. Validation of the Croatian version of the Sense of Coherence 29-item scale in Croatian nurses. 
Zdr Varst. 2020;59(3):155-163. doi: 10.2478/sjph-2020-0020.
ABSTRACT
Keywords: 
Sense of Coherence, 
SOC-29 instrument, 
validity, reliability, 
occupational 
medicine, nurses
IZVLEČEK
Ključne besede: 
občutek koherentnosti, 
SOC-29, veljavnost, 
zanesljivost, medicina 
dela, medicinske sestre
Introduction: The aim of the study was to validate the Croatian version of the Sense of Coherence 29-item instrument 
(SOC-29) within a nursing population.
Methods: The cross-sectional study was conducted between December 2017 and June 2018 at the University 
Hospital Centre Sisters of Mercy (UHCSM) in Zagreb, Croatia. A total of 711 nurses participated in this study. Internal 
consistency reliability was evaluated using Cronbach’s alpha coefficient (α), while the structure of the questionnaire 
was verified by exploratory factor analysis (EFA) (method of extraction: principal component analysis (PCA)) and 
confirmatory factor analysis (CFA).
Results: The instrument demonstrated high internal consistency (α=0.885). PCA analysis has identified five factors 
that together account for 48% of the variance. However, the observed factors could not be interpreted. In the CFA, 
none of the models fitted well, although the fit of the three-factor model (CMIN/DF=4.786, CFI=0.767, RMSEA=0.073) 
was slightly better in comparison with the one-factor model (CMIN/DF=6.072, CFI=0.685, RMSEA=0.084). As the 
three-factor model in PCA has been shown to be uninterpretable, and all three factors were mutually positive and 
significantly correlated (correlation coefficients: 0.365-0.521), this indicated a single factor in the background. All 
items also showed saturation with the first factor (accounting for 25.7% of the variance).
Conclusions: The Croatian version of the SOC-29 instrument successfully fulfilled the necessary psychometric criteria 
for being used on the population of Croatian nurses. The study proposes that potential users use the single-factor 
structure.
Uvod: Želeli smo ovrednotiti, ali je hrvaška verzija dolgega vprašalnika o občutku koherentnosti (SOC-29) uporabna 
v raziskavah na področju promocije zdravja med hrvaškimi medicinskimi sestrami, zato smo si zadali za cilj oceniti 
izbrane psihometrične lastnosti instrumenta v tej določeni poklicni skupini tako z vidika zanesljivosti kot tudi z 
vidika veljavnosti.
Metode: Presečna raziskava, v kateri je sodelovalo 711 medicinskih sester, je bila izvedena v obdobju od decembra 
2017 do junija 2018 v Univerzitetnem kliničnem centru Sestre milosrdnice v Zagrebu na Hrvaškem. Na področju 
zanesljivosti se je ocenjevala notranja skladnost. Uporabili smo Cronbachov alfa koeficient (α). Na področju 
veljavnosti se je ocenjevala struktura vprašalnika. Preverjala se je najprej s preiskovalno faktorsko analizo (EFA) 
(z metodo analize glavnih komponent (PCA) kot metodo ekstrakcije dejavnikov) in nato še s potrditveno faktorsko 
analizo (CFA).
Rezultati: N a p o d r o č j u z a n e s l j i v o s t i j e a n a l i z a p o k a z a l a v i s o k o n o t r a n j o s k l a d n o s t i n s t r u m e n t a ( α = 0 , 8 8 5 ) . N a 
področju veljavnosti je analiza PCA pokazala pet dejavnikov, s katerimi se je skupaj dalo pojasniti 48,0 % variance, 
vendar opazovanih dejavnikov ni bilo mogoče razložiti. Tudi ko smo PCA omejili na tri dejavnike, teh ni bilo mogoče 
razložiti. V CFA noben od modelov ni najbolje ustrezal, čeprav je bila ustreznost trifaktorskega modela (CMIN/DF 
= 4,786, CFI = 0,767 , RMSEA = 0,073) nekoliko boljša v primerjavi z enofaktorskim modelom (CMIN/DF = 6,072, CFI 
= 0,685, RMSEA = 0,084). Ker se trifaktorskega modela v PCA ni dalo interpretirati , prav tako pa so bili vsi tri je 
dejavniki medsebojno pozitivni in so bistveno korelirani (korelacijski koeficienti: 0,365-0,521), je to kazalo en sam 
dejavnik v ozadju. Vse postavke so pokazale tudi nasičenost s prvim dejavnikom, s katerim se je dalo pojasniti 25,7 
% variance.
Zaključek: Hrvaška različica instrumenta SOC-29 je uspešno izpolnila potrebna psihometrična merila za uporabo v 
populaciji hrvaških medicinskih sester, njenim potencialnim uporabnikom pa je predlagana uporaba enofaktorske 
strukture, ki jo je zagovarjal tudi avtor instrumenta, prav tako pa so prednost enofaktorski strukturi dali tudi 
številni drugi avtorji.

1 INTRODUCTION
The Sense of Coherence (SOC) is a key concept of 
salutogenic model proposed in 1979 by the American-
Israeli medical sociologist Aaron Antonovsky (1). It was 
seen as a coping resource that helped individuals to 
identify and use their external and internal resources 
for solving problems and managing life events (1). In 
order to measure the SOC, Antonovsky developed a 
special instrument: the Orientation to Life questionnaire, 
also named the SOC scale. The original version of the 
instrument consisted of 29 questions (SOC-29), while 
a shorter version contained 13 questions (SOC-13) (2). 
Current research by Mittelmark et al. indicates that the 
SOC-29 and SOC-13 have been used in at least 49 different 
languages in at least 48 different countries around the 
world (2). Both instruments were also assessed for their 
reliability and validity in different population groups, from 
the general population to various groups of patients (2-9). 
The results of validation studies proved both instruments 
to be reliable and cross-culturally appropriate tools (2-4). 
In these studies, a one-factor structure was often tested 
against a three-factor structure. Some authors have 
concluded that the SOC scale is more appropriate as a 
one-dimensional scale (3, 7), while others have suggested 
a multidimensional concept (2).
Research has proved that nurses constitute a vulnerable 
population group that faces significantly more stress 
compared to other professions (10), which may have a 
negative impact on their health (3-9, 11-14). Research 
findings on SOC in the nursing profession have so far shown 
that SOC is a protective factor against stressors in the work 
environment (15). A strong SOC is also a good predictor 
of nurses’ ability to function healthily in the workplace, 
protecting them against burnout (16). Burnout is also 
a feature of the nursing profession in Croatia (11, 17). 
According to Mijakoski et al. (17), Croatian nurses reported 
high levels of depersonalisation and of organisational 
and emotional work demands. The study highlighted 
the need for specific organisational interventions to be 
implemented in hospital settings. An exploration of SOC 
among Croatian nurses is therefore urgently required. 
In 2005 the SOC-29 was translated into Croatian (SOC-29-
CRO) and psychometrically tested on the sample of 822 
individuals from the general population (18). It has not, 
however, so far been used to assess the Croatian nursing 
population. Moreover, to our knowledge the literature 
currently contains only a handful of studies that attempt 
to validate the SOC-29 among nurses (19, 20). The study 
aimed to validate the SOC-29-CRO for use as part of health 
promotion research among Croatian nurses. Its objective 
study was to assess selected psychometric characteristics 
of the instrument within this particular occupational group.
2 METHODS
2.1 Study Design and Study Population 
This cross-sectional study was carried out as part of a 
larger research project on the impact of SOC on work ablity 
of nurses at University Hospital Centre Sisters of Mercy 
(UHCSM) in Zagreb, Croatia between December 2017 and 
June 2018. The total population of 1,465 nurses of different 
profiles (registered nurses, Bachelors of nursing, Masters 
of Science in nursing) employed in different departments 
of the UHCSM were considered for inclusion in the study 
regardless of their education level. However, due to 
various absences (sick leave, annual leave, study leave), 
questionnaires could only be delivered to 1,300 nurses.
2.2 Description of the SOC-29 Study Instrument
SOC-29 is an instrument with 29 items, each of them being 
scored on a seven-point scale (1) (Table 1). Thirteen items 
are formulated negatively and have to be reversed in 
scoring. The measure given by SOC-29 is a summary score, 
obtained by adding the values of individual responses 
to all 29 items, ranging from 29-203 points, with higher 
scores indicating a stronger SOC (2, 3).
Written permission to use SOC-29-CRO was obtained from 
the translators, as well from the copyright holders of the 
original SOC-29 instrument.
2.3 Instrument Administration
After obtaining the approval of the Ethics Committee, 
a meeting was held at which the participants were 
informed of the objectives of the research and the overall 
procedure. After the meeting, all study instruments were 
distributed in sealed envelopes to all hospital departments. 
Participants were given the possibility of taking the 
questionnaire home, filling it in and returning it to the 
workplace. All questionnaires were returned anonymously 
in sealed envelopes to protect nurses’ privacy. 
2.4 Psychometric Validation
In order to assess the instrument’s reliability, internal 
consistency was assessed by calculating Cronbach’s 
alpha coefficient (α). The instrument was considered 
to be internally consistent if α≥0.80 (21). In order to 
assess the instrument’s validity, the factor structure of 
the instrument was assessed by using exploratory factor 
analysis (EFA) as well as confirmatory factor analysis 
(CFA). In EFA, the data screening, assumption testing and 
sampling adequacy were performed first using the Kaiser-
Meyer-Olkin (KMO) statistic with appropriate values >0.5 
and Bartlett’s sphericity test with appropriate values 
p≤0.05 (22). The Kolmogorov-Smirnov (K-S) test was also 
performed for testing the normality of distributions. The 
principal component analysis (PCA) was then used as the 
extraction method. In CFA, the robust maximum likelihood 
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Table 1. Sense of Coherence 29-item instrument: items, their placement within three dimensions, and scoring (1).
Legend: *= the questions from the questionnaire are reprinted with the permission of the copyright holder; C=comprehensibility; 
Ma=manageability; Me=meaningfulness; O=original; R=reverse
Item_1
Item_2 
Item_3 
Item_4 
Item_5
Item_6 
Item_7 
Item_8
Item_9
Item_10
Item_11 
Item_12 
Item_13
Item_14
Item_15 
Item_16 
Item_17 
Item_18
Item_19 
Item_20 
 
Item_21
Item_22
Item_23
Item_24
Item_25 
Item_26 
Item_27 
Item_28 
Item_29
When you talk to people, do you have the feeling that they don’t understand you? 
Think of the people with whom you come into contact daily, aside from the 
ones to whom you feel closest. How well do you know most of them? 
Has it happened in the past that you were surprised by the 
behaviour of people whom you thought you knew well? 
In the past ten years your life has been: (full of changes without your 
knowing what will happen next – completely consistent and clear)
Do you have the feeling that you are in an unfamiliar situation and don’t know what to do? 
When you face a difficult problem, the choice of a solution is: (always 
confusing and hard to find – always completely clear)
Your life in the future will probably be: (full of changes without knowing 
what will happen next – completely consistent and clear)
Do you have very mixed-up feelings and ideas? 
Does it happen that you have feelings inside you would rather not feel? 
Does it happen that you have the feeling that you don’t know exactly what’s about to happen? 
When something happened, have you generally found that: (you overestimated 
or underestimated its importance – you saw things in the right proportion)
In the past, when you had to do something which depended upon cooperation with others, 
did you have the feeling that it: (surely wouldn’t get done – surely would get done)
Has it happened that people whom you counted on disappointed you? 
Do you have the feeling that you’re being treated unfairly? 
What best describes how you see life: (one can always find a solution to 
painful things in life – there is no solution to painful things in life)
When something unpleasant happened in the past your tendency was: (“to 
eat yourself up about it” – to say “OK that’s that, I have to live)
When you do something that gives you a good feeling: (it’s certain that you’ll go 
on feeling good – it’s certain that something will happen to spoil the feeling)
Do you think that there will always be people whom you’ll be able to count on in the future? 
Many people – even those with a strong character – sometimes feel like sad sacks 
(losers) in certain situations. How often have you felt this way in the past? 
When you think of the difficulties you are likely to face in important aspects of 
your life, do you have the feeling that: (you will always succeed in overcoming 
the difficulties – you won’t succeed in overcoming the difficulties)
How often do you have feelings that you’re not sure you can keep under control? 
Do you have the feeling that you don’t really care about what goes on around you? 
Life is: (full of interest – completely routine)
Until now your life has had: (no clear goals or purpose at all – very clear goals and purpose)
Most of the things you do in the future will probably be: 
(completely fascinating – deadly boring)
When you think about your life, you very often: (feel how good 
it is to be alive – ask yourself why you exist at all)
Doing the things you do every day is: (a source of deep pleasure 
and satisfaction – a source of pain and boredom)
You anticipate that your personal life in the future will be: (totally 
without meaning or purpose – full of meaning and purpose)
How often do you have the feeling that there’s little 
meaning in the things you do in your daily life? 
C
C 
C 
C 
C
C 
C 
C
C
C
C 
Ma 
Ma
Ma
Ma 
Ma 
Ma 
Ma
Ma 
Ma 
 
Ma
Me
Me
Me
Me 
Me 
Me 
Me 
Me
R
O 
R 
O 
O
O 
O 
O
O
O
O 
O 
R
O
R 
O 
R 
R
R 
R 
 
O
R
R
O
R 
R 
R 
O 
O
Item no Question* Dimension Scoring

estimator was applied and the following fit measures used 
in the assessment: the relative chi-square (chi-square/
degree of freedom) (CMIN/DF), the comparative fit index 
(CFI), and the root mean squared error of approximation 
(RMSEA). The criteria for fit measures were: CMIN/DF<5 
(23), RMSEA<0.060 (24) and CFI>0.950 (24). Two models 
were defined and tested: the one- and three-factor model.
Statistical analysis was performed using SPSS software, 
version 23.0 (SPSS Inc., Chicago, IL, USA), except for the 
CFA, where AMOS software was used.
3 RESULTS
3.1 Study Participants’ Characteristics
Of the 1,300 nurses eligible for inclusion, 713 participated 
in the study (response rate 54.7%). The group consisted 
of 630 women and 83 men. The mean age was 38.4±12.5 
years (range: 19-65 years). All other characteristics of the 
study participants are presented in Table 2.
10.2478/sjph-2020-0020 Zdr Varst. 2020;59(3):155-163
158
The SOC-29-CRO instrument was completed by 711 
participants. The mean value of the SOC-29-CRO summary 
score in our study was 145.0±22.1 points. The coefficient 
of relative variation was 15.2%. The statistical properties 
of the distribution of the individual item values are shown 
in Table 3.
Table 2.
Table 3.
Socio-demographic and work-related characteristics 
of the study participants (n=713).
Statistical properties of the distribution of values of 
items of the Sense of Coherence 29-item scale in the 
validation study of Croatian nurses (n=711).
Gender
Age
Marital status
Level of 
education
 
Work 
department
 
Length of 
service
Item_1
Item_2
Item_3
Item_4
Item_5
Item_6
Item_7
Item_8
Item_9
Item_10
Item_11
Item_12
Item_13
Item_14
Item_15
Item_16
Item_17
Item_18
Item_19
Item_20
Item_21
Item_22
Item_23
Item_24
Item_25
Item_26
Item_27
Item_28
Item_29
Male
Female
19–30
31-40
41–50
51–65
Married
Divorced
Widowed
Single
Life partnership
High school education
Bachelor of nursing
Master of nursing
Internal unit
Surgery unit
Operating room
Intensive care unit
Gynaecology unit
Polyclinical unit
Oncology and 
haematology unit
Dermatology unit
Emergency unit
Ophthalmology unit
Psychiatry unit
Paediatrics unit
Less than 1 year
1–19 years
20 or more years
4.8
4.6
3.8
3.8
4.8
4.7
4.3
5.6
5.0
4.8
4.6
5.2
3.8
4.5
5.6
5.0
4.9
5.8
4.4
5.1
5.0
4.6
3.8
3.8
4.8
4.7
4.3
5.6
5.0
1.6
1.4
1.4
1.7
1.6
1.4
1.5
1.5
1.7
1.7
1.4
1.4
1.5
1.8
1.5
1.7
1.7
1.5
1.4
1.4
1.7
1.4
1.4
1.7
1.6
1.4
1.5
1.5
1.7
5
5
4
4
5
5
4
6
5
5
6
5
4
5
6
5
5
6
5
5
5
5
4
4
5
5
4
6
5
4–6
4–6
3–5
3–5
4–6
4–6
3–5
5–7
4–6
4–6
5–7
4–6
3–5
3–6
5–7
4–7
4–6
5–7
3–6
4–6
4–6
4–6
3–5
3–5
4–6
4–6
3–5
5–7
4–6
83
630
247
161
159
145
371
48
18
186
89
429
256
28
179
157
33
73
52
23
58 
13
27
28
34
31
23
391
299
11.6
88.4
34.6
22.6
22.3
20.4
52.0
6.7
2.5
26.1
12.5
60.2
35.9
3.9
25.3
22.2
4.7
10.3
7.3
3.2
8.2 
1.8
3.8
4.0
4.8
4.4
3.2
54.8
41.9
Characteristic
Item
Category N (%)
x SD Me IQR
Legend: x=mean; s=standard deviation; Me=median; 
IQR=interquartile range

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3.2 Psychometric Validation 
3.2.1 Reliability
Cronbach’s alpha coefficient was high (α=0.885), indicating 
high internal consistency of the instrument.
3.2.2 Factor Structure
Both the KMO statistic (KMO=0.913) and Bartlett’s 
sphericity test (p<0.001) indicated adequate properties for 
the PCA. The K-S test did not show statistically significant 
deviations from the normal distribution (p=0.063). 
PCA analysis has identified five factors which together 
accounted for 48% of the variance (Table 4). However, the 
observed factors could not be interpreted. A PCA limited 
to three factors also showed an uninterpretable structure.
Table 4. Results of exploratory factor analysis (extraction method: principal component analysis) in the validation study of the Sense 
of Coherence 29-item scale among Croatian nurses (n=711).
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
25.700
33.962
39.801
44.063
48.005
25.700
8.262
5.839
4.262
3.943
7.453
2.396
1.693
1.236
1.143
25.700
33.962
39.801
44.063
48.005
51.393
54.687
57.910
61.003
63.903
66.699
69.345
71.846
74.261
76.610
78.827
80.975
83.021
84.968
86.854
88.695
90.471
92.095
93.640
95.079
96.419
97.680
98.869
100.000
25.700
8.262
5.839
4.262
3.943
3.388
3.294
3.223
3.092
2.900
2.797
2.646
2.500
2.415
2.349
2.217
2.147
2.046
1.947
1.886
1.842
1.776
1.623
1.546
1.439
1.340
1.261
1.189
1.131
7.453
2.396
1.693
1.236
1.143
0.982
0.955
0.935
0.897
0.841
0.811
0.767
0.725
0.700
0.681
0.643
0.623
0.593
0.565
0.547
0.534
0.515
0.471
0.448
0.417
0.389
0.366
0.345
0.328
Component
Cumulative % Cumulative % % of variance
Initial Eigenvalues Extraction sums of squared loadings
% of variance Total Total
The statistical properties of both models defined and 
tested using CFA are presented in Table 5. None of the 
models fitted well (Table 5). Moreover, all three factors 
in the three-factor model were mutually positive and 
significantly correlated (r=0.365-0.521).

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Additionally, in PCA all the items have shown first factor, 
which accounted for 25.7% of the variance (Table 4), 
loading. The factor loadings, which were considered 
satisfactory, are shown in Table 6.
4 DISCUSSION
The results of our study show that the SOC-29-CRO 
successfully fulfilled the required psychometric criteria 
for being used within the Croatian nursing population.
The results of the reliability analysis in our study are 
consistent with the results reported in other similar 
studies. First, the reliability obtained in our study is in 
the upper range of values for this measure obtained in 
other similar studies in general (range 0.70-0.95) (2-5). 
Table 5. Results of confirmatory factor analysis in validation 
study of the Sense of Coherence 29-item scale among 
Croatian nurses (n=711).
Legend: CMIN/DF=relative chi-square (chi-square/degree of 
freedom); CFI=comparative fit index; RMSEA=root mean squared 
error of approximation
Chi-square
Degrees of freedom
p
CMIN/DF
CFI
RMSEA
2289.11
377
<0.001
6.072
0.685
0.084
1790.13
374
<0.001
4.786
0.767
0.073
Statistical property one-factor model three-factor model
Table 6. Factor loadings greater than 0.200 in the validation study of the Sense of Coherence 29-item scale among Croatian nurses 
(n=711).
Item_1
Item_2
Item_3
Item_4
Item_5
Item_6
Item_7
Item_8
Item_9
Item_10
Item_11
Item_12
Item_13
Item_14
Item_15
Item_16
Item_17
Item_18
Item_19
Item_20
Item_21
Item_22
Item_23
Item_24
Item_25
Item_26
Item_27
Item_28
Item_29
 
-0.325
 0.257
-0.416
-0.394
-0.216
 0.266
-0.362
-0.225
-0.203
 0.244
 
-0.340
-0.290
-0.236
-0.306
-0.292
 0.383
 0.315
 0.217
 0.210
 0.219
 0.340
 0.209
 
 0.320
 0.262
 0.626
 0.392
 0.600
-0.301
 0.203
-0.317
-0.210
-0.260
-0.207
-0.223
 0.363
 0.521
 0.277
 0.241
 0.404
 0.246
 0.527
 0.383
-0.204
 0.317
-0.211
 0.337
 0.240
-0.352
-0.310
-0.355
-0.243
-0.266
-0.404
 0.310
0.443
0.342
0.352
0.277
0.483
0.468
0.305
0.547
0.565
0.399
0.515
0.542
0.403
0.512
0.520
0.497
0.496
0.581
0.500
0.589
0.430
0.355
0.551
0.626
0.677
0.718
0.625
0.667
0.345
Component
2
t
5
st
1
st
Component loads
4
st
3
t

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Finally, the results of our study are similar to the results 
of the study conducted among Portuguese nurses with a 
reported Cronbach’s alpha value of 0.87 (19). The reliability 
obtained in our study is also completely consistent with 
the reliability obtained in the study by Kardum et al. (18). 
The value of Cronbach’s alpha coefficient in this study was 
almost identical (α=0.88). 
The analysis of factor structure in our study first identified 
five factors (a similar result was obtained in the studies 
conducted by Frenz et al. (7) and Paika et al. (5). In both 
studies in continuation one-factor structure was revealed. 
In the study by Frenz et al., subsequent analysis of the 
factor scores suggested the scale had one core factor. The 
authors stated that the results suggested that the SOC was 
best understood as having a single core factor (7). Paika 
et al. repeated the factor analysis using the fixed number 
of factors as the extracted model, which resulted in one 
factor being extracted. Their study revealed that an SOC-
29 one-factor structure showed a coherent structure with 
remarkable stability (5). The study conducted among 
Portuguese nurses also confirmed the one-factor structure 
(19). As in our study all the items showed saturation with 
the first factor, we decided to use the one-factor structure 
advocated by other authors (5, 7). This was despite the 
fact that the percentage of the explained variance could 
not be considered satisfactory. However, we can justify 
this by the fact that we investigated a specific sample, i.e. 
a population of nurses employed in a precisely designated 
hospital. The coefficient of relative variation for SOC 
can also be considered low. Unlike our study, the study 
by Kardum et al. (18) showed a three-factor structure. 
However, in their conclusions they drew on the use of the 
overall result rather than the three components. This was 
because they discussed the inadequacy of their functional 
differentiation. In order to make a comparison with this 
study, we also tested a three-factor model. However, 
the three-factor structure deviated significantly from the 
structure advanced by other authors and, in our case, also 
proved uninterpretable, despite the rotations. For this 
reason, we decided to adopt the one-factor structure. 
These leads us to conclude that authors generally prefer 
the one-factor structure of the instrument. The one-factor 
model was also advocated by Antonovsky himself, since 
the instrument was not intended to measure dimensions 
individually (1).
Since the SOC-29-CRO has been already validated among 
the Croatian general population (18), it is important 
to explain why the authors considered it necessary 
to validate the instrument again on a specific nursing 
population. The first reason has been already presented: 
in the first SOC-29-CRO validation study, the factor 
structure of the instrument was not clear, even though 
the authors had proposed that a one-factor structure be 
used. This ambiguity could be the result of the internal 
heterogeneity of the sample of the general population. 
Consequently, we decided that it was important to re-
examine the factor structure on a specific population 
(like the nursing population addressed in this study) for 
the purposes of further research. The nursing population 
predominantly consists of women who are of reproductive 
age, have a higher level of education and are also exposed 
to extremely high levels of workplace stress (12). A study 
on the perception of stress conducted in Slovenia, a 
country similar to Croatia, found that employed women 
with at least college-level education were at very high risk 
of suffering from frequent stress perception (25). Various 
studies show that differences exist between the genders 
as regards experience of stress, with women estimating 
stressors as more severe than men and tending to report 
higher rates of psychological distress (26). The reason for 
this may lie in the fact that employed women have to 
cope with various roles in their professional and private 
lives and that their experience of the environments 
in which they live and work is probably different from 
that of men. It is therefore reasonable to conclude that 
this group deviates very significantly from the general 
population, which could also be reflected in the results of 
the instrument validation.
Our study has some potential limitations. First, one can 
argue that this study only includes nurses from one hospital 
in Croatia. A counter-argument would be that this hospital 
is a typical large healthcare institution that employs a 
large number of nurses of different profiles. This allows 
in-depth research into health problems related to the 
nurses’ workplace. Second, the response rate/number of 
participants was towards the lower recommended limit, 
but nevertheless still within the values that allow robust 
correct conclusions to be drawn. Third, one could argue 
this study used no method of measurement of stability 
of the instrument over time, e.g. the test-retest method. 
We counter this by the fact that the reliability of any 
self-reported outcome measure can be evaluated using 
measurement stability methods and/or measurement 
equivalence methods. The latter were developed from 
social science research for situations in which it was not 
possible to perform repeated measurements because the 
measured phenomenon had changed or could change over 
time (27). Finally, one can argue that this study tested only 
one- and three-factor models. Our argument here is that, 
in accordance with the existing theoretical assumptions 
(2), the results of other studies (2-5, 7, 8) that have the 
confirmed one- and three-factor structure of the SOC 
questionnaire, and with the results of PCA in our study, 
it was rational to test only the one- and the three-factor 
models.
The study also has several important strengths, the most 
prominent being that it provided additional and important 
information and knowledge about the psychometric 

10.2478/sjph-2020-0020 Zdr Varst. 2020;59(3):155-163
162
properties of the SOC-29-CRO when evaluated in a Croatian 
nursing population. The study showed the one-factor 
structure more directly than the study on the general 
population. As a result, the one-factor structure of the 
SOC-29-CRO can be more reliably used in subsequent 
research on nurses. Finally, the fact that the study was 
conducted among the nurses of a single hospital only can be 
an advantage as well as a limitation, since this institution 
is similar to many other institutions in countries that are 
experiencing similar transition processes to Croatia. The 
results of this study could apply to these hospitals as well, 
especially those in the countries of former Yugoslavia. 
The study results are significant for occupational medicine, 
health organisations and nursing management in Croatia 
and beyond. Nurses are often exposed to occupational 
hazards in their work environment which can lead to 
stress (11). The outcome of these stressful events depends 
on how nurses cope with stress. Weak SOC prevents 
nurses from actively managing stressful events, which can 
lead to work-related health problems. The SOC-29-CRO 
instrument could be used by nursing managers to identify 
nurses with weak SOC and implement interventions to 
create healthy working environments and protect and 
promote nurses’ health. Actively managing nurses’ health 
can help to increase their work ability. This instrument 
could also be helpful when planning the introduction of 
coping strategies among nursing students as well as among 
students of other healthcare professions, since it has 
already been proven that high levels of perceived stress 
predispose health students to anxiety and a lower quality 
of life (28). A number of challenges remain for those 
studying the use of SOC-29-CRO in nursing populations. 
The dynamics/stability of the SOC-29-CRO must first be 
checked over a longer period of time in time, especially in 
relation to those nurses with more demanding jobs (e.g. in 
intensive care departments). With a focus on studying the 
properties of the SOC-29-CRO in the nursing population, 
our work could usefully be continued by analysing 
additional aspects of validity, e.g. criterion validity.
5 CONCLUSIONS
The adequate psychometric properties of the instrument 
indicate that SOC-29-CRO is a reliable tool for use in further 
research. In the near future, it may also be important to 
the process of designing measures for enhancing nurses’ 
internal resources for the management of workloads.
ACKNOWLEDGEMENTS
The authors are grateful to all the nurses who took part 
in the survey.
CONFLICTS OF INTEREST
The authors declare no conflicts of interest.
FUNDING
The study received no funding.
ETHICAL APPROVAL 
The study was approved by tthe University Hospital 
Centre Sisters of Mercy  (reference no EP-7811/16-19). The 
research was carried out in accordance with the ethical 
principles of the Helsinki Declaration. All respondents 
gave their informed consent to participate in the study.
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