Study design and setting
The present study is a methodology research which aims to develop psychometrically analyze “general perception of Covid-19 risk (GPCOVID-19R) questionnaire in April 2020. This questionnaire has been prepared based on four stages of Schneider et al. (2004) (30, 31)
2.1 │Context, concept definition
.The first step: In order to achieve an operational definition of the concept of risk perception a conventional qualitative content analysis study was used. 10 experts in various specialties related to public perception of risk of Covid-19 disease participated in semi-structured interviews. In that study, 3 PhDs in disaster and emergency management, 1 psychologist, 3 members of the study population, 2 nursing educators and 1 cleric. The contents of the interviews were analyzed based on the approach of Graneheim& Lundman (2004) Using the latent content method (32).
2.2 │ Item development process
Second step: The items of the public COVID-19 risk perception questionnaire were created based on the features in the operational definition of the concept, literature review, and the results of studying the factors affecting Iranians' risk perception of COVID-19 (29). The literature review was performed by searching in databases such as Web of Science, Pub Med, Science Direct, and Google Scholar search engine without any time limitations using the keywords of risk perception, crisis, natural disaster, and risk perception questionnaire.
2.3 │ Statistical analysis/ Psychometric evaluation
In the third step of the research, three methods of face, content, and construct validity were used to ensure the validity of the questionnaire.
Face validity (qualitative and quantitative): In the qualitative method, the questionnaire was emailed to 10 participants and they were asked to give their opinions on the difficulty level, appropriateness level, and ambiguity of each item. After modifying some items based on the opinion of participants, face validity was quantitatively reviewed in the next step using item impact method. In the item impact method, if the obtained score for each item is equal to or more than 1.5, the statement is considered appropriate and will remain in the questionnaire (23, 24). In this step, 9 items were eliminated.
Content validity: Qualitative and quantitative methods were used respectively to review the content validity. In the qualitative method, the evaluation instruments included grammatical correctness, using proper words, importance of items, and putting the items in their proper places. At this point, the questionnaire which consisted of 56 items were emailed along with the operational definitions of their main components to 5 experts who had experience in qualitative work and tool-making, and disaster health experts. Modifications were made based on their suggestions. In the quantitative content validity method, content validity ratio and content validity index were employed.
Content validity ratio (CVR): The Lawshe model was utilized in this study (33), and experts were asked to review each item based on a 3-part scale (it is essential, it is useful but not essential, it is not essential). Based on the Lawshe Table (For evaluation of 5 experts), a minimum acceptable value of 0.99 was considered (34-36). CVR strict method was used in this study, which means that only essential items with put in the content validity ratio formula (37). At the end of this stage, only 32 items were left.
Content validity index (CVI): Experts were asked to review each item in terms of relativity to the intended concept on a 4- point Likert response (from not being relevant to completely relevant). In this research, S-CVI/Ave was calculated. That is, the ratio of items that received a score of 3 or 4 from all the experts, items that received a score of 0.79 and bigger, were kept. Items with a score of 0.7 to 0.78 were modified and revised, and others were taken out (38). At the end, 26 times remained.
Construct validity: Exploratory and confirmatory factor analyses were performed using Amos software version 23. Exploratory factor analysis (Varimax orthogonal rotation method) was used to investigate the internal relationship of variables and to discover variable categories that have the highest correlation (39, 40). Factor analysis is one of the most important steps in designing new instruments (41). The cut-off point of 0.30 was considered in this study as the minimum factor load to maintain the statement extracted from factor analysis. After reviewing the construct validity, 20 items were confirmed for GPCOVID-19R questionnaire.
In the fourth step, the internal consistency method (Cronbach's alpha) was used to determine the reliability of the questionnaire. Cronbach's alpha indicates the appropriateness of the group of items that measure a construct. For a good and sufficient internal consistency, the Cronbach's alpha should be between 0.7 and 0.8 (22).
2.4 │ Participants / Sampling Method
Sampling size: In the confirmatory factor analysis (CFA), the sample size should be at least 5 to 10 samples per variable (34). Therefore, the sample size in this study with 26 items was 300 people.
Inclusion and Exclusion Criteria: The inclusion criteria included being Iranian, an internet user, and willingness to participate in the study, and the exclusion criterion was not completing the questionnaire.
Data Collection: The population under study included all internet users who were members of Telegram and WhatsApp groups. Sampling methods were convenience sampling (available) and snowball sampling and participation was voluntary. With cooperation from the group's administrator, the link to the online COVID-19 RPRQ (address: https://samadi.porseshnameonline.com/form/q2) was pinned to the top of those groups that the researchers themselves were members of. The group administrator encouraged members to fill out the questionnaire and at the end, they were asked to post the link of the questionnaire in other social media groups.
The questionnaire consisted of two parts: demographics (5 questions) and risk perception question part which was consisted of 26 items with five-choice Likert answers (agree, somewhat agree, no opinion, somewhat disagree, disagree).
Iranians' GPCOVID-19R questionnaire was made available to internet users in Tehran for two weeks, starting from March 25th (45 days after the first official COVID death in the city of Qom). A total of 304 questionnaires were completed.
Ethical considerations: Ethical considerations were voluntary participation and anonymous questionnaires. Only one code was assigned to each questionnaire, thus the identity of the user was preserved. Filling out the questionnaire was completely optional and users could exit the study whenever they felt reluctant to continue by clicking on the "completed" button.