The following specific review questions (RQ) have been defined:

What periods and geographical areas are covered by the identified publications?

We searched the following seven databases: (1) Medline via PubMed; (2) Web of Science; (3) Scopus; (4) ABI/INFORM via ProQuest; (5) APA PsyclInfo via EBSCO; (6) CINAHL via EBSCO; (7) Business Source Complete via EBSCO. The search strategy was developed iteratively. We combined terms from two core themes: (1) hospital manager AND (2) competency. Multiple synonyms were used for each theme (Supplementary Table S1). We searched for terms in the title and/or abstract published since 2000. The search was conducted in June 2022. The reference lists of publications included in the review were manually searched to find additional studies of interest. In addition, websites of international organizations active in the field of health management and scientific journals on this topic were also manually searched (Supplementary Table S2).

Publications were selected in two steps: screening of abstracts and assessment of full texts based on predefined inclusion and exclusion criteria. Studies were included (1) if they dealt with the competencies of senior and middle-level hospital managers; (2) if they were peer-reviewed empirical studies, theoretical papers, technical reports, expert opinions/guidelines books, chapters or dissertations; and (3) if the full text was in English. They were excluded if: (1) they did not focus on the competencies of middle- or senior level hospital mangers (this exclusion covered, among others, three main subcategories: studies on first-line hospital management physicians/nurses practice managers/coordinators, clinical team managers/leaders, defined in our review as those who have having direct contact with patients; studies on managers working outside the hospital settings – e.g. in primary, community, or long-term care; studies examining the knowledge or attitudes of hospital managers, but in some narrowly defined areas such as, waste management and infection control); (2) had the incorrect type of publication (book reviews, commentaries, cover letters, conference abstracts, or other types publications that are not full texts); (3) full texts in were in another language. The justification behind decision to exclude studies on mangers involved directly with patent care – e.g. case managers (defined by us as first line managers) was based both on the review’s focus on hospital managers with the greatest influence/decision making power on the organization as a whole and on the pragmatic approach of not mixing organizational management competencies with those related to direct patient care, e.g., within coordinated care programs. The decision to exclude studies focusing on hospital managers’ knowledge in some narrowly defined topic, like waste management was also based on our review more comprehensive approach to competencies.

Two researchers (CN and AH) participated in both phases in parallel (to compare the selection and assess the level of agreement). In case of disagreement, a third researcher (KDJ) was involved in the process, to discuss and reach a final agreement. The designated software was used (Mendeley and Rayyan).

Data extraction tables were developed using MS Excel forms and tailored to the type of publications included (separate tables were used for empirical studies and other types of publications). Each section of the extraction table was matched with the specific research question. The extraction was also conducted independently by two researchers (CN and AH), then compared and finalized. Supplementary Table S3 provides an example of the data extraction table for empirical studies.

Both quantitative and qualitative methods (thematic analysis) were used for data analysis and synthesis. The included publications were grouped according to predefined categories. The codes assigned in the extraction table were used for quantitative summaries. For example, based on the main focus of empirical studies, three categories were distinguished: (1) studies on the types or classifications of hospital managers’ competencies; (2) measurement of competencies; and (3) the relationship between competencies and hospital-level outcomes. The results of the review were compiled in the form of tables.

The preliminary findings were presented at the internal seminar at the authors’ institution in December 2022, attended by 40 hospital managers and healthcare management experts. The purpose of the consultation was to validate the results and provide directions for further, in-depth research.

Searches in seven databases yielded 9,764 records (Supplementary Tables S4–S10 show the search results for each database). A further 22 records were identified through manual searches of relevant organizations and journal websites. After removing duplicates, 4,378 records were screened for titles and abstracts, after which 189 publications were retrieved for full-text analysis. A total of 42 publications met the inclusion criteria. Screening of the reference list led to the inclusion of 15 additional articles. Thus, 57 publications were included in the final synthesis (9, 10, 12, 16, 18, 23–74). A PRISMA flow chart of the results is attached (Supplementary Figure S1). Supplementary Table S11 provides a list of all included studies by year, country, and type of publication, as well as the full reference information.

The 57 publications include 46 empirical studies (10, 23–63, 71–74), six literature reviews (12, 16, 18, 64–66), four publications classified as expert opinions/guidelines (9, 67–69) and one dissertation (70). The publications were published between 2002 and 2022, with the majority (60% or 34/57) published since 2015 (Figure 1).

Five of the six included literature reviews have been published since 2015. Two reviews (64, 66) did not report the number of included studies, while the others included between 12 and 33 studies. The review of various aspects of competencies of senior and middle-levels healthcare managers was the focus of all six reviews (Supplementary Table S12). Three reviews investigated the types or classifications of competencies required by hospital managers in specific thematic areas {e.g., leadership (12), value-based care (16) or general competencies in a small number of specific countries [e.g., developing countries (18)]}. One review provided a rather broad overview of issues related to competency-based education and training for health care managers (64). The remaining two reviews (65, 66) analyzed healthcare managers’ leadership competencies. The four expert guidelines provided recommendations on general competencies for hospital management, all focused on United States (US) health system (9, 67–69). Finally, the PhD thesis (70) was also from the US and analyzed the scope of managerial competencies that drive successful change initiatives using several empirical examples.

Table 1 shows the general overview of 46 empirical studies. Geographically, most studies were from Asian countries (36% or 16/ 46), followed by the Americas (n = 10), Australia (n = 9), Africa (n = 6), and Europe (n = 4) (Supplementary Figure S2). One study included countries from two different geographical regions (i.e., different continents), namely Brazil and Australia (44). When broken down by country, 57% (n = 26/46) of all studies were from only three countries, namely Iran (n = 10), Australia (n = 9), and the United States (n = 7).

Of the 46 empirical studies (shown in Table 1), 34.8% (16/46) contained information on the types/classifications of hospital managers’ competencies, 30.4% (14/46) included information on their measurement, 30.4% (14/46) included both of these two aspects, and one study examined both types of competencies and their relationship simultaneously. The latter identified the levels of decision-making and problem-solving skills of hospital administrators and determined the interrelationships between these skills and other administrative skills (57). Only one empirical study focused exclusively on examining the relationships between hospital managers’ characteristics (including competencies) and resource management capacity (72). Most studies (38/46) focused on the competencies of senior-level hospital managers, including 23 that analyzed the competencies of senior and middle-level managers simultaneously.

Of the 45 studies that focused on the types and/or measurement of hospital managers’ competencies, 60% (27/45) used quantitative methods (mostly surveys and questionnaires, followed by statistical analyses), 17.8% (8/45) used qualitative methods (interviews with thematic analysis), and 22.2% (10/45) used a mixed-methods approach. Majority of studies reported that both ‘hard competencies’ such as specific technical knowledge (44, 48) or skills acquired through practical training (41, 44, 63, 72), and ‘soft competencies,’ e.g., adaptability (63), leadership (30, 43, 48, 67, 69), effective communication (9, 30, 44, 45, 48, 67, 69), teamwork (9, 30, 44), time management (43–45, 72), creativity (43, 44, 48), and decision-making (43, 67), are needed for effective hospital management. As a consequence, many researchers pointed out the importance of both ‘external’ formal education training/certificates as well as ‘internal’ peer-support, mentoring, and/or coaching as complementary competency improvement approaches.

The majority of studies that focused on measuring the level of hospital managers’ competencies applied a quantitative approach (79%, or 22/28). The researchers either developed their own questionnaire/survey for the purpose of their study (n = 15/28) or used existing tools (n = 10/28). Examples of existing, validated tools included the Management Competence Assessment Tool for Health Care Managers (MCAP) used in three studies (38, 39, 41), and the questionnaire designed by the International Hospital Federation (IHF) used in two studies (28, 54). The first includes elements related to professionalism and is divided into six core competencies: (1) evidence (evidence-based decision-making); (2) resources (operation, administration, and management of resources); (3) knowledge (knowledge of organizational health environments and communications); (4) interpersonal communication skills and relationship management; (5) leadership (leadership of people and organizations); and 6. change (enable and manage changes). The IHF questionnaire consists of 80 competencies contained within five domains, namely: (1) business, (2) communication and relationship management, (3) health and healthcare environment, (4) leadership, and (5) professional and social responsibility. In all studies, the measurement of the level of competencies was “subjective” – hospital managers themselves rated their competencies. An additional ‘cross – check’ component was added in five studies (36, 38, 39, 56, 61). The latter included either an additional survey conducted among supervisors (61) or a 360-degree feedback process (36, 38, 39, 56). In the latter case, hospital managers’ competencies were also assessed by their peers [e.g., community managers (36)].