The WHO framework on health system performance assessment is based on the concept of health action, and encapsulates any set of activities whose primary intent is to maintain or improve population health, enhance the system's responsiveness to the expectations of the population, and assure fairness of financial contributions to the system. To achieve these main goals, four functions are performed by health systems: financing, stewardship, service provision and resource generation (see Fig. 1).
In particular, health system financing refers to the process by which revenues are collected from primary and secondary sources, accumulated in fund pools and allocated to provider activities. Stewardship involves the aspects of setting, implementing and monitoring the rules for the health system; assuring a level playing field for all actors in the system (particularly purchasers, providers and patients); and defining strategic directions for health systems as a whole. Service provision is the combination of inputs into a production process that takes place in a particular organizational setting and that leads to the delivery of interventions. Resource generation refers to the production of inputs – particularly human resources, knowledge, and physical resources such as facilities, equipment and consumables – for the provision of services. While HRH are directly or indirectly related to each of these four functions and influenced by them, in this paper we will concentrate on assessing HRH inputs as they pertain to the latter two.
Different elements should be borne in mind when selecting and calculating appropriate indicators for HRH monitoring and evaluation. From the perspective of human resources as an input to health action, HRH can be broadly defined as "the stock of all individuals engaged in the promotion, protection or improvement of population health" [4]. This encompasses those working across different domains of health systems: public and private sectors; clinical, research and public health interventions; preventive and curative personal care; etc.
In general terms, a number of criteria have been identified as crucial for selecting indicators, including policy relevance, reliability, validity, simplicity and ability to aggregate/disaggregate information [10, 11]. Indicators on HRH are used for various purposes, such as measures of planning, implementing, monitoring and evaluating policies. To facilitate both the data collection and analysis processes, it is important to focus on a limited and essential number of indicators that are comparable and measurable regularly using standard data sources.
A series of components for selecting HRH indicators for the performance of the services provision and resources generation functions can be found in Fig. 2. The proposed list follows the general framework of health system performance assessment, classified in terms of the level of achievement, distribution (equity) and efficiency (productivity) of HRH [12]. This list is not meant to be exhaustive, nor is it necessarily expected that all these indicators will be used in any given HRH assessment. This will depend on the user's particular circumstances, with the eventual number reduced to an essential minimum in accordance with data availability and quality. This basic basket of indicators is also not intended to be restrictive, and focuses on indicators appropriate for quantitative analyses. Other indicators may be used as appropriate in the context of national and local operations or different types of study designs.
Detailed descriptions of the key indicators, including formulas and potential sources for measurement, can be found in the Additional file. Depending on the data sources and classifications used, many of these indicators can be disaggregated by occupation (physicians, nursing and midwifery professionals, etc.), by administrative units (districts, provinces or states, etc.) or other sociodemographic characteristics (age, sex, etc.). At the same time, indicators for some topics highly relevant to HRH analysis must be further investigated and tested. This includes measures of labour relations or dissatisfaction (such as work stoppages or other absences), regulation of health professions (such as rules to ensure standards of training and practice), financing of HRH production (such as fairness of financing for training programmes), risk factors to health workers (such as susceptibility to violence or to contracting infectious diseases including HIV/AIDS) and physical conditions (such as lack of materials or state of the workplace).
Indicators of the health service provision function
Level
A range of indicators can be defined to measure specific aspects of the level of HRH as an input to improving the provision of health services. The starting point of many HRH assessments is the stock of health personnel. Indicators of stock or available supply are usually expressed in terms of densities of HRH with regard to the total population or the population of economically active age. The distinction lies in the capacity of the system versus the allocation of human resources to the system compared to those available. Skill-mix indicators are also commonly used to measure various HRH components in relative terms. These indicators, which can provide a pointer of the priorities and capacities of the system, compare one subgroup to another according to assumed differences in skill levels or skill specializations, such as the ratio of physicians to nurses, or of specialists to generalists.
External migration of health workers, especially highly skilled ones, has long been recognized as a problem for ensuring appropriate coverage of essential services in some countries. The proportions of foreign-born or foreign-trained among the national HRH stock constitute simple but informative indicators on the importance of international immigration within the health sector. On the other hand, they fail to capture the impact of emigration on sending countries or migratory trajectories among workers, which tend to be difficult to measure because of a general lack of reliable and comparable data from source countries.
The participation or not of those with a health-related vocational background in the labour market, and their ensuing participation in the health industry in particular, offer important information for health policy purposes. Indicators on labour force activities capture three main elements: participation (the proportion of individuals with health-related skills currently in the labour force), employment opportunities (the proportion with health-related skills currently employed), and retention (the proportion with health-related skills currently working in a health-related industry). Complementary indicators may include the proportion of health workers engaged on a part-time basis, or the proportion with more than one current job.
Another aspect of labour force activity is the categorization of institutional sector of the work location, usually as public or private sector operations. The public sector includes government-operated facilities and services, while the private sector consists of for-profit or not-for-profit activities implemented by private agents or businesses as well as nongovernmental organizations and religious or other charitable institutions. However, the distinction is not always clear-cut, with some health systems having publicly-owned facilities staffed mainly by privately operating health workers, or large numbers of health professionals working partly in the private sector and partly in the public sector (with this arrangement sometimes being part of their contract with the latter).
Information on income or wages among health workers is of value when discussing countries' health care financing options. In many countries wage costs (salaries, bonuses and other payments) are estimated to represent between 65% and 80% of renewable health system expenditures [13, 14]. A common indicator is the average annual income or occupational earnings. This can be measured in gross or net terms, depending on the nature of the data source. In order to account for differences in working times, an alternative indicator might be constructed as average hourly wages (gross or net). Other complementary indicators for assessing monetary incentives could refer to modes of remuneration (for example, the proportion of health care providers paid by salary, fee-for-service or capitation), or multiplicity of sources of remuneration (such as the proportion of health workers receiving wages from both public and private sector jobs).
Distribution (equity)
A breakdown of HRH by workers' sociodemographic or other characteristics can offer insight into imbalances within the health workforce. Inequitable occupational distributions by geographical location and by gender constitute the main areas of health policy concern for many countries. Geographical imbalances, and especially shortages in rural or poor areas, are reported to have a number of adverse consequences for health systems performance. Other complementary indicators for assessing equity in the health workforce include distributions of vacancy rates, turnover rates and relative wage rates by location (or other criteria).
Occupational clustering by gender is regarded as important not only for assessing equity in human resources opportunities, but also for health services planning. A distinctive feature of HRH in many countries is the high proportion of workers who are women. Studies have shown that increased participation of women in the medical field may be accompanied by differences in working patterns: female physicians are likely to work fewer hours than their male counterparts [15, 16] and to present different styles of care provision that may be reflected in the levels of patient participation [17]. Moreover it has been suggested that certain female-dominated occupations, notably in nursing and midwifery, often are not given a market value commensurate with their skill level, as the work is seen simply as "women's work" [18]. Analysis of gender imbalances in average occupational earnings may reveal the extent to which women and men have equal opportunities in career choice. Indices of inequality might also be used to highlight extremes across income distributions, which may be masked when considering averages alone.
Efficiency (productivity)
Increasing the productivity of health workers has been identified as one of the most cost-effective ways to improve health system capacity and performance [19]. Indicators of productivity include measures such as the ratio of workers' time spent providing health care services as compared to non-care services (meetings, travelling, reporting, etc.), the average number of ambulatory visits per working hour among providers of direct patient care, or the average number of immunizations administered per day by a given provider. Such indicators may reflect in part the intensity of work activities among health care providers, but different values for the indicators may also reflect differences in the underlying reality – for example, linked to the manner in which work is organized or the pattern of ailments. Complementary indicators of productivity may include the average number of hours worked per week among health workers, the ratio of health workers engaged on a part-time basis versus full-time basis, or the ratio of average working time among clinical staff to less-costly support staff.
Indicators of the resource generation function
Level
The proportion of those starting or completing training in a health-related field with respect to the total HRH stock offers insight into the renewal and loss patterns of the health workforce. Monitoring information about entrants/graduates at health training institutions enables anticipation of future HRH supplies in relation to exits due to retirement or external migration. Such indicators may be disaggregated by skill specialization, such as the ratio of entrants/graduates of medical programmes versus nursing programmes. In some cases, where information on numbers of academic entrants/graduates is difficult to obtain, a substitute indicator may be used as the proportion of the total HRH stock in the youngest age groups. This proxy measure can be used to assess the importance of ageing in the health workforce. However, cross-national and cross-occupational comparability may be hindered by differences in the average duration or age of academic training, where the number of trainees who eventually seek employment in the (national) health sector is low, where the number of workers trained abroad is high, or where there is considerable mobility in and out of the workforce over the active age span.
Assessing the education and training levels of the health workforce is a key element for policy-makers. The advance of complex health systems organizations and medical knowledge, as well as the introduction of sophisticated technology, mean that improvements in population health and welfare increasingly depend on the degree of educational attainment and renewal and maintenance of technical capacity among the health workforce. Education-relevant indicators for HRH assessment include the proportion of health workers with a tertiary-level educational attainment and the proportion having undertaken a continuous education course or programme within a specific period. It should be noted that such indicators may fail to capture the notion of quality of education and training and its adequacy regarding the needs of the population and the health care system.
Distribution (equity)
Equity indicators for resource generation show the proportional distribution of new entrants or graduates at health training institutions according to different criteria – for example, the distribution of health trainees according to gender, or their distribution in urban versus rural areas. Monitoring the latter can be especially crucial for assessing policy impacts in terms of imbalances and incentives for staffing in remote geographical locations.
Efficiency
The decision to train more students in the field of health has important financial consequences. The training costs per student might be substantial, especially for physicians and specialists, who must attend medical school for several years to acquire the proper qualifications. Measures of the current average and marginal financial cost of training allow projections of the total costs of training more students, and can be used to compare training costs within and across countries. This can refer to vocational training at tertiary-level educational institutions or through continuous education programmes. A complementary efficiency indicator could be the attrition rate at health training institutions – that is, the ratio of entrants to graduates per academic programme.