*2.2. Participants and Sample*

Our study population included the healthcare professionals who worked in the various services offered in the Castellón Province in both private and public healthcare. According to the most recently available data, in 2019 there were 2959 registered nurses and 2667 medical practitioners (doctors). No data are available about other groups, such as nursing assistants, and data do not differ between public and private systems or between the different types of center and service [21]

#### *2.3. Variables*

An online survey devised with Google Docs was forwarded. It included 28 questions arranged into different blocks. The first block of seven questions asked the professionals if they thought that healthcare quality had worsened, remained the same, or had improved during the state of alarm. They were also asked to assess the impact of different factors on healthcare quality (workload, human resources, material resources, teamwork, patients' clinical complexity, and healthcare organization). These questions were answered on a 5-point Likert-type scale (1: Strong negative impact; 5: Strong positive impact).

The second block contained 11 questions about managing human and material resources. The professionals were asked to assess on an ascending 5-point Likert-type scale (1: Not at all appropriate; 5: Most appropriate) the staff reinforcement contracts signed and contract duration. They were also asked to assess on an ascending 5-point Likerttype scale the availability of different material resources (surgical gloves, protective face shields, impermeable gowns, cleaning and disinfecting products, and other material resources). Two questions were included about the training received in handling PPE and cleaning/disinfecting products.

The third block comprised 10 questions about how health care was organized during the state of alarm. They were asked to specifically assess on an ascending 5-point Likerttype scale (1: Not very appropriate; 5: Most appropriate) how centers' management responded, supervisors' direct concern about work teams' well-being, how work was organized, the clarity of protocols, and the suitability of the circuits set up to attend to COVID-19 patients. Two questions were also included about the training received in the new organization of both work and teamwork. The professionals were also requested to assess if their occupational rights and conditions were respected during the state of alarm. Finally, they were asked to assess if the health system was ready to face a new outbreak.

We collected socio-demographic variables: age, gender, and family responsibilities (children, elderly people, dependent people), as well as perceived health status (very good, good, normal, bad). Occupational variables were also included, such as type of center (public; private), the health department they belonged to (HD1; HD2; HD3), healthcare service (primary care center; hospital; nursing home; others (healthcare transport or private offices, among others)), their professional category (doctor; nurse; nursing assistant; others (hospital porter or technicians, among other)), their contract type (temporary; permanent; contracted specially for the pandemic; substitution; resident in training; other), years of experience (less than 5; between 5 and 10; between 10 and 15; more than 15), and other variable related to COVID-19 exposure (positive case, diagnosis technique, isolation).
