3.1 | Characteristics of the participants
In the first round of investigation, the average age of clinical nursing staff was (32.25 ± 6.48) years old, with 1585 females accounting for 92.58% and 127 males accounting for 7.42%. In the second round of the survey, the average age of clinical nurses was (33.09 ± 6.36) years old, with 134 males, accounting for 13.05%, and 893 females, accounting for 86.95%. Other Demographic features are shown in Table 1.
3.2 | Preliminary exploration of the scale
3.2.1 | Item analysis
As shown in Table 2, the results of item analysis of the 1712 questionnaires to preliminary explore the scale in the first round showed that the values of each item in item analysis were up to the standard and all the items were to be reserved.
3.2.2 | Exploratory factor analysis
Based on the item analysis, exploratory factor analysis was employed to preliminarily identify the structure of the nursing staff's biosafety incident response competence scale.
Kaiser-Meyer-Olkin(KMO)analysis
The KMO value was 0.984, the Bartley Sphericity test was statistically significant (c2 =99415.926, df=1176, P<0.001), indicating that 49 items of nursing staff's biosafety incident response competence scale had common factors and were suitable for factor analysis.
Factor Extraction and Rotation
Principal Component Analysis was used to extract factors and varimax was used to rotate factors to extract components with eigenvalues higher than 1. And we removed the highest factor load less than 0.4, factor load across two or more factors and the difference less than 0.2, and the number of common factors included items less than 3 [21]. According to the delete criteria, items 8, 9, 10, 14, 21, 26, 27, 31, 34, 35, 36, 37, 38, 39, 40, 41 were deleted, and 4 common factors were extracted. The cumulative contribution of variance accounted for 73.427%.
Based on the item analysis and exploratory factor analysis, a preliminary scale of nursing staff's biosafety incident response competence was developed, which includes 4 factors and 33 items. 4 factors were named at the group meeting as follows: biosafety knowledge preparedness, biosafety event monitoring and warning abilities, biosafety infection protection abilities and biosafety incident nursing disposal abilities, as shown in Table 3.
3.3 | Further exploration and evaluation of the scale
3.3.1 | Item analysis
This section used the same method for item analysis. The results showed that item 21 met the deletion criteria and was intended to be deleted after discussion by the research group, and other items were to be reserved. As shown in Table 2.
3.3.2 | Exploration of Scale Structure
On the basis of item analysis, we further explored the structure of the scale. The gravel plot of exploratory factor analysis shows that the scale exhibits inflection points between components 3~5. Based on the initial structure of the conceptual model, a 4-factor model was preliminarily extracted, as shown in Figure 2.
The results of principal component analysis of each dimension revealed that among the factors of each dimension, only one had an eigenvalue greater than 1. The variance contribution rates ranged from 68.311% to 76.246%, and the load value of each dimension item was greater than 0.4, as shown in Table 4.
514 questionnaires were randomly selected from the 1027 questionnaires, and exploratory factors were analyzed by principal component analysis. Bartlett sphericity test yielded a value of 16383.411, and the KMO test value was 0.970 (P<0.01). The results showed that the eigenvalues of the 4 factors were 17.925, 2.798, 1.491 and 1.128, and the variance contribution rates were 56.015%, 8.744%, 4.658% and 3.524%. The cumulative contribution of variance rate was 72.941%. However, items 9 " Regularly participate in the education of biosafety-related science knowledge ", 8 " Regularly participate in biosafety medical rescue exercises and training and joint military and civilian rescue exercises to deal with emergencies ", and 10 " Regularly pay attention to the biosafety frontier, and regularly participate in the training of biosafety nursing skills " were classified as the first common factor, belonging to the same category as items 19, 18, 17, 15, 12, 11, 13, 14, and 20, considering that common factor 1 corresponds to the model's "monitoring and warning ability". Considering that items 8, 9, and 10 do not belong to the same category as factor 1, 'Biosafety event monitoring and warning abilities', the research group deleted items 8-10 after discussion.
On the basis of preliminary exploratory factor analysis, the scale included 4 dimensions and 29 items. We conducted exploratory factor analysis again. We randomly selected 514 questionnaires from 1027 valid questionnaires for exploratory factor analysis. The results showed that the Bartlett sphericity test value of the scale was 30410.372, and the KMO test value was 0.973 (P<0.01). The characteristic values of the four factors are 16.885, 2.370, 1.436, and 1.088, respectively, with variance contribution rates of 58.224%, 8.174%, 4.950%, and 3.751%, and cumulative variance contribution rate of 75.100%. The cumulative variance contribution rate had been improved compared to the preliminary exploratory factor analysis, and the items included in the 4 factors conform to the theoretical model, as shown in Table 5.
3.3.3 | Reliability analysis
The scale and its 4 dimensions demonstrated good reliability. The overall internal consistency was 0.974, and that of each dimension ranged from 0.888 to 0.964. The total split-half reliability was 0.885, and of each dimension ranged from 0.856 to 0.917. To ensure comparability, we randomly selected 10% of the nursing staff and labeled them, and compared the selected nursing staff with the general nurses in Demography data, the difference was not significant (P>0.05), indicating that the samples were comparable with the general samples. A questionnaire study was conducted on these 10% of nursing staff who were re-distributed the scale again after a 2 weeks interval. The results showed that the total retest reliability of the scale was 0.840, and the retest reliability of each dimension was 0.696~0.881. As shown in Table 6.
3.3.4 | Validity analysis
Content validity
15 experts in the field of biosafety were invited to evaluate the content validity of the scale. The results showed that the I-CVI was 0.800~0.933, and S-CVI was 0.866.
Structure validity
The remaining 513 questionnaires in the second round of investigation were selected for confirmatory factor analysis. The 4-factor model was fitted by the maximum likelihood estimation method. The fitting indexes were shown in Table 7, and the standard factor load model formed by confirmatory factor analysis was shown in Figure 3. The factor load of each item was greater than 0.40, and all items had statistical significance (P<0.05), indicating that the questionnaire had good structural validity.