Having been translated into 27 languages, CLES+T is now used in more than 40 countries [25]. In this study we propose the Polish version of this research instrument, as it displays good validity and reliability levels and can be recommended for use in the evaluation of CLE, supervision, and the role of nurse teacher in postgraduate nursing education. Cronbach’s alpha for the Polish version of the scale was 0.97. Cronbach’s alpha coefficient for the CLES+T sub-dimensions ranged from 0.83 to 0.95. These results are in line with other validation studies performed in culturally similar environments. For example, in the Slovak version, Cronbach’s alpha of the 34-item CLES+T was 0.94, and Cronbach’s alphas for each of the five subscales ranged from 0.80 to 0.97 [26]. In the Croatian version, the overall Cronbach’s alpha of 33 items was 0.97, and Cronbach’s alphas for each of the subscales ranged from 0.77 to 0.96 [1]. In the Slovenian version, the overall Cronbach’s alpha of 34 items was 0.96, and Cronbach’s alphas for the subscales ranged from 0.78 to 0.94 [25]. However, it should be underlined that all of the previous studies took place in an undergraduate education context.
In our own research, a five-factor structure was confirmed in accordance with the assumptions adopted by the authors of the original version of the scale. The five-factor model with the explanation of 67.9% of the total variance in our study was comparable to the factorial models of other studies in Europe. To provide some examples – in the original, Finnish version: 64% of the total variance [5], in the Spanish version: 66.4% of the total variance [27], in the Cypriot version: 67.4% of the total variance [28], and in the Slovenian version: 67.69% of the total variance [25]. The four-factor model of CLES+T resulted from Croatian validation study and explained 71.5% of the total variance [1], in Austrian studies with explanation of 73% of the total variance [2], and in German studies with explanation of 72.85% of the total variance [29].
The strongest factor in studies on the Polish version of CLES+T was the sub-dimension the content of supervisory relationship with high loading from 0.741 to 0.891, explaining 51.1% of variance. This factor was identified as the strongest also in other validation studies of CLES+T [5, 27, 28, 29, 30, 31]. The sub-dimension role of the nurse teacher was found to be the second strongest factor in our study, with loading from 0.337 to 0.905 and the explanation of 5.8% of variance. This is in line with the Cypriot study in which this factor explained 11.02% of variance [28].
The weakest factor in this study was the leadership style of the ward manager (3.2% of variance explained), a result similar to that in the Cypriot studies [28] and opposite to the German studies in which this factor was the second strongest [30]. In other studies, the weakest factor was usually nursing care on the ward [5, 27, 31].
The individual item means in our study varied between 4.24 and 4.79 and can be considered as relatively high, especially when compared with Swedish results where the individual item means ranged from 2.4 to 4.4 [30]. The mean results for individual subscales in Polish research were also calculated, as follows: for pedagogical atmosphere: 4.56±0.54, for leadership style of the ward manager: 4.58±0.65, for nursing care on the ward: 4.52± 0.63 (the lowest), for the content of supervisory relationship: 4.70±0.53, and for role of the nurse teacher: 4.73±0.45 (the highest). These results show that the work of educators responsible for the entire clinical training process (an internship supervisor and a postgraduate course coordinator) is duly recognised and acknowledged. In a Spanish study among nursing students, the means for all subscales were generally lower than in our study. The lowest mean was calculated also for the subscale nursing care on the ward: 3.38±1.01, while the highest for pedagogical atmosphere: 4.15±0.63 [27]. At the same time, in a Finnish study involving 1973 healthcare students, similarly to our results, the means for subscales were relatively high, although still lower than in the Polish one. As opposed to our study, however, the highest mean was calculated for nursing care on the ward: 4.56±0.55 and the lowest for role of the nurse teacher: 3.98±0.87 [3].
Limitations
This study has its limitations, the main one being the convenience sampling method. Nurses taking part in the study were recruited from only one region of Poland and one educational institution which, in the case of our study, was a postgraduate education centre for nurses and midwives. Therefore, the sample of nurses was too homogenous to allow the formulation of conclusions of a more general nature. Research in a more diverse group of respondents is recommended. Additionally, the test-retest reliability of the scale – an important measure for the scale development – was not assessed in our study and it is recommended for future research.