The first paper in this series on building the field of Health Policy and Systems Research (HPSR) in low- and middle-income countries (LMICs) [1] outlined the scope and questions of the field and highlighted the key challenges and opportunities it is currently facing. This paper examines more closely one key challenge, the risk of disciplinary capture—the imposition of a particular knowledge frame on the field, privileging some questions and methodologies above others. In HPSR the risk of disciplinary capture can be seen in the current methodological critique of the field, with consequences for its status and development (especially when expressed by research leaders).

The main criticisms are reported to be: that the context specificity of the research makes generalisation from its findings difficult; lack of sufficiently clear conclusions for policy makers; and questionable quality and rigour [2]. Some critique is certainly warranted and has come from HPS researchers themselves. However, this critique also reflects a clash of knowledge paradigms, between some of those with clinical, biomedical, and epidemiological backgrounds and those with social science backgrounds. Yet, as HPSR is defined by the topics and questions it considers rather than a particular disciplinary approach, it requires engagement across disciplines; indeed, understanding the complexity of health policy and systems demands multi- and inter-disciplinary inquiry [3].

To develop the science of HPSR it is, therefore, important to start by recognising the diversity of disciplinary perspectives, as well as shared concerns. Richer methodologies for addressing these concerns must then be developed. And, as health policies and systems are themselves social and political constructions, it is important to acknowledge the particular value of social science perspectives in the field. Each of these issues is addressed in the following sections, and they are considered further in paper three of the series [4].

Figure 1 characterises key areas of difference between the dominant knowledge paradigms that underpin the disciplines applied within HPSR. The figure deliberately polarises the paradigms to spark debate. Some disciplines are dominated by a particular paradigm and some are spread across paradigms.

The positivist worldview is reflected in much clinical, biomedical, and epidemiological, and some social science, research. This view starts from the same position as the natural and physical sciences. The phenomena being investigated comprise a set of facts, a single reality that can be observed and measured by the researcher without disturbing them. The central aim of research is to detect causal mechanisms through the deductive process of testing hypotheses derived from theory and past experience against empirical facts. At their simplest, such mechanisms represent the prediction that “x will cause y” in any other setting. Simple HPSR hypotheses might include, for example, “limited financial incentives cause low motivation” or “a lack of health facilities undermines access to health services.” Sometimes such hypotheses are tested through statistical analysis of secondary data [5]; sometimes studies are designed to allow hypotheses to be tested [6]. Indeed, the positivist perspective underpins the recent rise of experimental methodology in impact evaluation. As the emphasis in such studies is on measuring the magnitude of an intervention's impact, and ensuring that this estimate is unbiased, careful attention is paid to selecting an appropriate control group (randomized or otherwise) and controlling the influence of possible confounding factors. Much less emphasis is placed on understanding how the intervention works and which contextual or other factors mediate its impact.

Much social science work that is qualitative is located at the relativist end of the spectrum. Such research is essentially based on the understanding that the world around us is subject to human interpretation. Health policies and systems are, therefore, understood to be constructed and brought alive by social actors through the meaning they attach to (their interpretations of) their experiences. Whereas positivist researchers focus on facts and regularities (that is, causes and effects), relativist researchers see interpretations as the primary subject of inquiry, proposing that different interpretations of the same experience represent multiple realities. In this tradition, researchers study human behaviour in everyday or natural settings, generating qualitative data that are primarily analysed inductively to generate categories and explanations of experience. Such analysis also involves interpretation by the researcher, in interaction with respondents. It may be guided by, and/or generate, what is called middle range theory, i.e., ideas about how the world works, comprising categories and concepts derived from analysis, and suggestions about how they are linked together. Middle range theory may be tested against evidence through the process of analysis or highlights questions and ideas to be considered in future studies.

Relativist HPSR studies focus, for example, on how health system actors understand and experience particular services or policies [7], and what social and political processes, including power relations, influence them [8],[9]. The development and testing of middle range theory is also supported by studies that adopt a critical realist position. This knowledge paradigm falls somewhere in the spectrum between positivism and relativism, and is of growing interest in HPSR [10] (see FEMhealth, http://www.abdn.ac.uk/femhealth/). However, these sorts of questions are still only quite rarely addressed in the wider HPSR literature [1].

Although HPS researchers from different disciplinary traditions have some difficulty understanding each other's perspectives, they also have some shared starting points: a common focus, health policies and systems, and a concern about how to strengthen health systems to benefit those being served by them. The complexity of the phenomena being investigated may also generate a willingness to think creatively about how to investigate issues. Therefore, HPS researchers tend not to fall at the extreme ends of the spectrum outlined in Figure 1—and this makes multi- and inter-disciplinary work more possible.

Review of existing HPSR work demonstrates, moreover, that bringing together research from different traditions generates broader and deeper understanding on the issues of focus. Box 1, for example, shows the breadth of questions that have been addressed around one critical HPS issue for LMICs, user fees; and the different papers examining the household level impacts of out of pocket payments together provide deeper and richer insights on these experiences than would come from one perspective alone.

Health policies and systems are fundamentally shaped by political decision-making, whilst the routines of health systems are brought alive through the relationships among the actors involved in managing, delivering, and accessing health care, and engaged in wider action to promote health, including researchers [11]. In essence, therefore, health policies and systems are constructed through human behaviour and interpretation, rather than existing independently of them. As relativist social science perspectives see all phenomena as at least partially constructed in this way, they have particular value in building the methodological foundations of HPSR. Three contributions are discussed here: generalising from rich contextual understanding; supporting policy learning; and approaches to ensuring research rigour.

The current interest in HPSR provides exciting opportunities for the field, but also brings the threat of “disciplinary capture” by the clinical, biomedical, and epidemiological disciplinary perspectives dominant in wider health research. Yet, social science perspectives are vital to HPSR. Health policies and systems are complex social and political phenomena, constructed by human action rather than naturally occurring. Advancing the science of HPSR, thus, demands we take steps to build understanding across disciplinary boundaries, for example, by ensuring that we can speak each other's languages around generalisability and knowledge generation; sharing experience of supporting policy learning; and clarifying expectations of each other's disciplinary culture. Valuing social science perspectives and building interdisciplinary understanding both represents the cutting edge of HPSR and demonstrates that the field is at a scientific cutting edge.