*3.3. Setting*

The research was conducted at the Ministry of Health's (MOH) hospitals (*n* = 10) in the Najran region, located in the southern part of the KSA.

#### *3.4. Population and Sample*

All nurses at the 10 hospitals included in the study were informed about the study by the nursing office director at each hospital. The participants were randomly included from the list of nurses working in each emergency department (ED), thus avoiding the bias of choosing a specific group. They were ensured that their participation was voluntary, they could withdraw from the study whenever they decided to, and the obtained data were handled confidentially. They received basic information about the study and its goals, and informed consent was obtained from each participant. A power analysis with a standardised statistical power of 0.80 and medium e ffect size of 0.5 premediated the appropriate sample size to 200 nurses. The self-completion questionnaire was presented to the participants through the SurveyMonkey website.

#### *3.5. Data Collection and Processing*

Collected data were stored at the hospitals' research centres. Nurses answered the questionnaires on a specific research day to prevent response influence. The respondents were asked to provide correct information. The information provided was subject only to research, and the researcher could not disclose the respondents' identities at any time, no matter the circumstances. The included participants were registered nurses working in EDs who were willing to participate, in all age and gender groups. Nurses who were not present during the study period because of vacation or maternity leave, nurses at the managerial level, and nursing aides were excluded.

All data concerning the 10 emergency preparedness competency dimensions were analysed by the authors. The primary investigator was responsible for collecting data and categorising them for further analysis by the teammate. Each dimension consisted of a number of questions, in which participants could indicate their familiarity with a topic based on a five-point Likert scale (see results).

## *3.6. Ethical Approval*

For this study, an ethical committee certificate of approval was obtained from the Institutional Review Board at the General Directorate of Health Affairs in the Najran region (IRB Log Number 2020-27 E—Date of approval: 1 July 2020).
