This exploratory psychometric study was conducted in the village of Beiragh, located in the suburb of Tabriz metropolitan city in 2018. The research community in this study includes livestock breeders living in the northern slope of Sahand Mountain in the south of Tabriz, all of whom are male. The village of Beiragh is in many ways is similar to the village of Lighvan, where our intervention study was to be conducted. Livestock breeders in this area breeder sheep and goats and rarely cattle. Livestock breeders, in addition to keeping ruminants, are also active in the production of dairy products. This village with a population of more than five thousand people and fifty thousand sheep and goats and by production about 10 thousand lambs and yeanling every year, has at least 2 veterinarians and 2 livestock vaccinators with more than forty cheese production workplaces is one of the main livestock breeders and dairy producers in the country.
The Ethics Review board at Tarbiat Modares University approved conducting the study.
Developing the Initial Questionnaire
Initial items of BPQ were achieved through a thorough literature review and interviews with all stakeholders. Databases, including MEDLINE, PubMed, EMBASE, ERIC, Cochrane Library and Cumulative Index of Nursing and Allied Health Literature (CINAHL) were searched to find any published study about brucellosis prevention or animal vaccination. A combination of keywords of "prevent*", "brucella*" and "vaccine*" were used to search in English and Persian. 816 published articles between 2008 and 2019 were obtained and after reading their abstracts and removing duplicate articles, 110 more relevant articles were read in full text. Having reviewed those papers and contacted the corresponding authors, nine Persian and three English questionnaires were obtained[15–17].
Interviews were conducted to identify the factors influencing preventive behavior of livestock breeders. The conceptual framework for conducting the interviews was the concepts from the first four phases of PRECEDE model [14]. Purposive sampling was employed to recruit participants [18] and directed content analysis was used to analyze the content of the interviews [19].
livestock breeders, health educationists, veterinarians and experts from a vaccine providing institute in the region, who were volunteer, participated in 30 to 45 minute face-to- face interviews. The interviews took place at participants' desired time and place. They were told that their information would be kept confidential and would be used anonymously. The items from literature review were combined with the findings from interviews Identical and duplicate questions were removed and some questions were edited. Finally, after three sessions of approximately 90-minute group discussions, consisting of health educationists, veterinarians and experts from a vaccine and serum production institute, One of the research team members acted as the coordinator of the sessions. Holding group discussion sessions, one of the researchers took notes. Then, a targeted analysis was performed on the interview content. The first draft of the research questionnaire was confirmed. Anchor response of the items were also discussed and finalized by research team members.
Assessment of face and content validity of the questionnaire
Face validity was examined both qualitatively and quantitatively. For qualitative assessment, based on the feedback from livestock breeders and health educationists, any ambiguity in the meaning, wording and scaling of the items, grammatical errors and errors in items allocation, were identified and resolved. For quantitative assessment, impact score (IS) of each item was calculated.
Livestock breeders and health educationists participated to assess the face validity of BPQ. Those livestock breeders were different from the ones, who participated later in assessing the construct validity of BPQ and those in the cross-sectional part of the study.
The accuracy and quality of different stages depended on the selection and employment of a group of experts. It was very important to choose specialists who had valid articles in the mentioned field or had work experience in this area. Therefore, we tried to select experts from different groups with the above mentioned qualifications to evaluate all aspects of content [20, 21].To evaluate the face validity of the items, the appropriateness of each item was rated by an expert, using a five-point Likert scale. Impact score of each item was calculated by the formula of:
Impact Score = Frequency (%) × Importance [22, 23]. for each of EFA and CFA at least 200 was the number of patients rated the item 4 or 5, while “importance” was the mean score of the item on the 1–5 rating scale.
Content validity of the questionnaire was also examined both qualitatively and quantitatively. For quantitative assessment of content validity, Content Validity Index (CVI) and the Content Validity Ratio (CVR) were calculated. To do so, BPQ was submitted to twenty experts. In this phase, BPQ was emailed to twenty veterinarians and health educationists to evaluate the content validity of the questionnaire and response rate was 95 percent. Concerning the precision of the data, two questionnaires were set aside. (Response rate= 0.85%).
CVI and CVR were calculated based on three and four part Likert scales, respectively. CVR was calculated by the formula of (Ne – N/2)/ (N/2) [23]. In this formula, N is the total number of panelists and Ne is the number of panelists who rated the item to be “essential”. Based on the Lawshe table, items with CVR below 0.46 were removed [24].
CVI of the items was calculated by the formula of
CVI=the number of specialists who assigned scores 3 and 4 to the items/N
Relevance of each item was rated by a 4-point Likert scale. Items with the CVI less than 0.79 were removed [25, 26].
Assessment of construct validity of the questionnaire
Construct validity of the questionnaire was evaluated by both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) for each of EFA and CFA at least 200 participants are required[27]. Sampling framework in the study included 450 livestock breeders living in the region. Due to the fact that livestock breeders deliver their dairy products to the dairy producing workplaces chosen by themselves, the complete list of the whole livestock breeders was taken from forty cheese producing workplaces in the village and stacked and their final list was provided to be used in random sampling. Random sampling of the relevant list was performed using)www.randomizer.org software (.Four hundred and fifty livestock breeders in Beiragh were randomly selected and voluntarily participated at this phase,50 of whom were more than needed considering the drop rate[27, 28].
Exploratory Factor analysis (EFA)
EFA was done on 42 binary items and 17 Likert-scale items, which were intended to explain ‘preventive behavior of livestock breeders. Principal component analysis and oblimin rotation method were used to determine the number of optimal factors. Loadings with the significance lower than 0.05 were excluded from the analysis [29]. If an item was loaded into different factors, it was related to the factor in which it had the largest factor loading. After the analysis, the questions were categorized. Each of the categories forms a structure which is reviewed by the research team and titled appropriately according to the nature of all questions and what characteristics they measure .The extracted factors were named by team members.
Confirmatory Factor analysis (CFA)
For the items with binary response anchors, the generalized confirmatory factor analysis [30] and WLSMV statistical estimation method were used [30]. The software of M-Plus- version 7.4 was applied to test and evaluate the intended conceptual model. Based on the basic concepts of the questions, their concepts and relationships (identified with the EFA), an initial categorization of the questions was performed and considered as a conceptual model. Based on 59 questions, 3 categories of awareness, attitude and practice were considered. Due to the lack of proper fit of the initial conceptual model, the awareness scale was divided into three categories: direct and indirect awareness and vaccine awareness. This classification was also evaluated and challenged by exploratory factor analysis, which has a correct basis in terms of statistical calculations. The proposed new model with 59 questions and 5 latent structures (direct and indirect awareness, vaccine awareness, attitude, and practice) was considered as a conceptual model and this conceptual model was evaluated and tested by confirmatory factor analysis in M-Plus software, in several stages by removing items with low factor loading and items with large common factor loadings in two unrelated structures and the final model was resulted and confirmed in 5 structures and 53 items as behavioral constructs.
The fitness of the proposed model was assessed by fit indices including the ratio of Chi-square to degrees of freedom (X2/DF), Root Mean Square Error of Approximation (RMSEA), Comparative Fit Index (CFI), and Tucker-Lewis Index (TLI). The values of at least 0.90 for CFI and TLI, and below 0.08 for RMSEA represented a good fitness [31, 32]. After excluding non-significant items, the final conceptual model was introduced.
Assessment of reliability of the questionnaire
Cronbach’s alpha coefficient and composite reliability (CR) were calculated for testing the internal consistency of the questionnaire. Stability of the results was examined by calculating the Interclass Correlation Coefficient (ICC) [23,24]. At least 30 participants are required to perform reliability[35] To evaluate the reliability of the questionnaire, available forty two volunteer livestock breeders in Beiragh consenting to participate in the questionnaires completed the research questionnaires. After 2 weeks interval, the questionnaires were were completed by the same people and statistically analyzed to assess the stability of the findings [34]. For the analysis of the absolute reliability of the results, standard error of measurement (SEM) was calculated. The IBM SPSS statistics 24 was used to perform data cleaning and calculating reliability indices. P values lower than 0.05 were considered significant.
The list of participants in each step is broken down.in Table 1.
Table 1. List of the participants in each of the phases
|
participants
|
result
|
Interviews
|
Six livestock breeders)male)
four health educationists(1male+3 females)
four veterinarians(3 males+1 female)
three experts from a vaccine providing institute(male)
|
identify the factors influencing preventive behavior of livestock breeders
|
group discussion
|
three health educationists (3 females)
three veterinarians(3 males)
two experts from a vaccine providing institute(male)
|
first draft of the research questionnaire was confirmed
|
Face validity (qualitative)
|
Fifteen livestock breeders (male)
seven health educationists (2males+5 females)
|
identified and resolved (ambiguity meaning, wording , grammatical errors and allocation)
|
Face validity (quantitative)
|
Fifteen livestock breeders (male)
|
Impact score (IS) of each item was calculated.
|
Content validity
|
Seven veterinarians )5 males+2 females)
three veterinarians and experts from a vaccine providing institute(male)
Seven health educationists( 2 males+5 females)
|
Content Validity Ratio (CVR)
|
Content validity
|
Seven veterinarians )5 males+2 females)
three veterinarians and experts from a vaccine providing institute(male)
Seven health educationists( 2 males+5 females)
|
Content Validity Index (CVI)
|
construct validity
|
212 livestock breeders (male)
|
exploratory factor analysis (EFA)
|
construct validity
|
220 livestock breeders (male)
|
confirmatory factor analysis (CFA)
|
reliability
|
42 livestock breeders (male)
|
(α),(ICC),(SEM),(CR)
|