Proposed Framework

Prior to undertaking this systematic review, a scoping study was conducted (Mikkelsen, 2010), which identified three theoretical domains that help explain the physician’s prescription behaviour: cognitive decision theories, economic theories and behaviour theories.

Decision making is important in medical practice, and because health outcomes are probabilistic, most decisions are made under conditions of uncertainty (Kaplan and Frosch, 2005, Elstein and Schwarz, 2002). Medical science has not yet solved the uncertainty surrounding many medical decisions (Gillett, 2004), and as a consequence, medical decision making is the least developed aspect of evidence-based practice (Spring, 2008). Furthermore, uncertainty has been characterized as the most important factor influencing physician behaviour (Arrow, 1963). Thus, uncertainty is central to Decision Theory concerned with medical decision-making.

In an intellectual project for understanding, (McGuire, 2001) has provided a comprehensive review of the topic from a health economic perspective.

Interestingly, the author concludes that economic models often ignore uncertainty and informational asymmetry inherent in modern health care (McGuire, 2001 p.

496). Perfect physician agency may exist if agent and principal have the same information; however, no demand on the quality of information is made. Thus, perfect agency can be based on imperfect information (Mitnick, 1994). According to Eisenhardt (1989), moral hazard refers to the lack of effort by the agent, and adverse selection refers to the misinterpretation of ability by the agent.

Asymmetry of information regarding these two aspects may be considered an advantage, and if used inappropriately, may be unbeneficial to the principal.

From an agency perspective, the physician may play the role of agent for several principals. First and foremost, the physician is an agent on behalf of the patient.

Asymmetry of information regarding diagnosis and treatment options is a natural consequence of the physician’s extensive training and resulting expertise. This training is complex, time consuming and costly, creating a situation where it is not possible for a patient to correctly verify quality or utility of health care provided. In other words, the provision of health care is experience goods. It has been argued that only about 25 % of patients are reasonably well informed about the care they receive (McGuire, 2001 p. 465). Physician agency may also exist with payers and/or employers as principals. Given the potential complexity of physician agency with several simultaneous principals, physician loyalty will be under pressure and may be influenced by shifting power between principals, thus having a bearing on patient health. However, the authority of the physician is still

2001 p. 463). In light of the central role played by physicians in medical decisions, it is important to consider aspects of moral hazard and adverse selection from an agency perspective.

The theory of reasoned action and its extension, the Theory of Planned Behaviour, is the most studied theoretical framework informing on the topic of physicians’ cognition leading to decision behaviour. In addition, Agency Theory plays a central role in defining contextual contributors to the decision making process. Despite being highly trained, doctors are prone to making mistakes, and cognitive biases may detract from the use of logical and statistical decision heuristics. Given the multidimensional theoretical framework having a bearing on medical decision-making, deciding how to decide is central.

The theoretical construct having a bearing on physician prescribing behaviour, therefore, should include Decision Theory (under uncertainty), Agency Theory and Theory of Planned Behaviour; please see Figure 3-3 Theoretical domains.

However, the Theory of Planned Behaviour speaks to attitude in the context of belief strength. It can therefore reasonably be argued that uncertainty from a Theory of Planned Behaviour perspective is a component of attitude.

Figure 3-3 Theoretical domains

Godin et al. (2008) argue convincingly that among cognitive behaviour theories, the Theory of Planned Behaviour has the highest predictive power for physician behaviour. However, the authors conclude that the theory has insufficiencies and propose a new framework; please see Figure 3-4 Hypothesized theoretical framework. The framework has explanatory power, as it provides a simple and credible explanation. It purports that physician characteristics, role, and identity are factors influencing behavioural intent. Furthermore, physician-level habit persistence is added as a separate factor modulating intent.

Decision  Theory

Theory of  Planned  Behaviour Agency 

Theory

Figure 3-4 Hypothesized theoretical framework

The framework proposed by Godin et al. (2008), as an extension to the Theory of Planned Behaviour, is not fully supported by the results of this review. The deficiency is highlighted by the fact that physician characteristics is not found to be a key factor influencing physician prescribing behaviour. Godin et al. (2008) argue that role and identity, beliefs about capabilities and past behaviour/habit are distinct from physician characteristics. From the findings in this review, two counter points are presented. First, role and identity is tightly linked with specialty, which has been found to be integral to the definition of physician characteristics. Second, beliefs about capabilities are related to attitude. Thus, only past behaviour/habit remains, which has been found to be a component of physician characteristics. In fact, habit persistence is found to be a strong influencer of physician prescribing behaviour, whereas other components of physician characteristics have not been found to influence physician prescribing behaviour. In addition, the framework proposal does not agree with the premise of dynamic decision making, as feedback is lacking from the framework.

Feedback from previous action is precisely what makes dynamic decision strategies effective (Kleinmuntz, 1993), and not including feedback limits the validity of the proposed framework.

The question that remains to be answered is whether the Theory of Planned Behaviour is a “good” fit for physician prescribing behaviour. In essence, the Theory of Planned Behaviour can account for the majority of the factors, but it does not account for habit persistence and information asymmetry; please see Table 3-5 Strength of Influence for further details. Habit persistence can be considered as residues of experiences and past behaviours. Information asymmetry is inherent to the practice of medicine, and when coupled with uncertainty, it is the driver of moral hazard and adverse selection. Furthermore, the theory lacks feedback or learning, and so discounts the temporal aspects of medical practice.

Thus, it may be argued that the Theory of Planned Behaviour does not fully explain the observed behaviours uncovered in this review. As proposed by Godin et al. (2008), further development of the Theory of Planned Behaviour is needed to fully explain physician prescribing behaviour. Based on the evidence uncovered in this review, the framework depicted in Figure 3-6 Proposed

conceptual framework is therefore proposed in order to explain physician prescribing behaviour.

The proposed framework is based on the evidence of influence uncovered in this systematic review. Furthermore, the model should be subject to operationalization employing qualitative methodology, and finally, quantitatively tested in a clinical setting. For instance, further research could focus on the model fit concerning prescribing pain medication for cancer patients. Further work would also be needed to ascertain the internally consistency of the model, and this may be the focus of future doctoral research. In addition, based on the fact that most (70%) of all physician-patient consultations result in the prescription of a medicine as part of the treatment, physician prescribing may be considered a proxy for medical decision making by physicians in general. Thus, it is also proposed to test whether the framework is a good fit for medical decision making by physicians in general.

In summary, the framework outlines how components from cognitive behaviour theory, Agency Theory and Decision Theory are interlinked to explain physician prescribing behaviour.

Figure 3-5 Strength of influence

Figure 3-6 Proposed conceptual framework

The proposed framework illustrated in Figure 3-6 Proposed conceptual framework is derived from the three theoretical domains (agency, decision under uncertainty and TPP) that help explain physician prescription behaviour and that were identified in the scoping study (Mikkelsen, 2010) and further substantiated by the evidence presented in this systematic review. Following an explanation of the conceptual framework, origin and flow of influence on behaviour in the context of physician prescribing is addressed.

TPP assumes that subjective norm, attitude and perceived control influence behavioural intent, the immediate antecedent to behaviour (Ajzen, 1991).

Subjective norm consists of normative beliefs that are influenced by the stakeholders, with a bearing on physician prescribing behaviour. The physicians’

perception of social normative pressures of whether to perform the behaviour or not is argued to be influenced by agency. Both the physician and patient are largely insulated from the economic realities of any decision made in the context of prescribing medicines. This creates a situation where conflict of interest exists between the physician and payer, and moral hazard may be present.

Furthermore, the inherent information asymmetry of agency may also lead to adverse selection (Eisenhardt, 1989). In this context, it could be argued that agency effects may in part be caused by an influence on social normative pressures, thus influencing physician prescribing. For example, patient expectations and the physician’s perception of patient expectations may lead to

From the TPP, it can be assumed that attitude consists of behavioural beliefs influenced by the probability of the behaviour producing the desired outcome, and the physician’s positive or negative self-evaluation of the behaviour, thus forming the attitude component of the theory (Ajzen, 1991). From a physician prescribing behaviour perspective, there is an overlap between the attitude component of the Theory of Planned Behaviour and the uncertainty inherent in any medical decision. Therefore, it may be argued that uncertainty modulates the perceived probability of desired outcomes as a result of behaviour.

Perceived control is a central element of TPB and represents the difference between TPP and the preceding theory of reasoned action. The concept is based on the assumption that an individual's perceived ease or difficulty of performing the particular behaviour is that perceived behavioural control is determined by the total set of accessible control beliefs; presence of factors that may facilitate or impede performance of the behaviour (Ajzen, 1991).

Intention is an indication of a physician’s readiness to prescribe, and it is assumed to be an immediate antecedent of prescribing behaviour. Behaviour is an individual physician’s observable response in a given situation with respect to prescribing. Ajzen (1991) claims that behaviour is a function of behavioural intent and perception of control. Perceived behavioural control is therefore assumed to moderate the effect of intention on physician prescribing behaviour. Thus, favourable intention produces a prescription only when perceived behavioural control is strong. For example, a physician will only prescribe medicines in the geographic area where he/she has a licence to practice.

Experience from own behaviour is expected to form the basis of a learning process which may influence future behaviour. “Learning is the process whereby knowledge is created through the transformation of experience” (Kolb, 1984, p.

38). Prior experience is expected to moderate future physician prescribing behaviour (Webb and Lloyd, 1994). In fact, physicians may exhibit overreliance on personal experience as compared to scientific data when prescribing (Soumerai et al., 2000). Thus, experience may feedback and moderate subjective norm, attitude and control beliefs. For instance, in cases where a physician has a positive experience with a medicine, with regards to efficacy and safety, this is likely to reinforce future prescriptions, and negative experiences will have the opposite effect.