Capability 5: complexity and uncertainty

Uncertainty is an inevitable consequence of using the holistic biopsychosocial model of illness as the analytic framework in rehabilitation. The rehabilitation expert needs to manage the uncertainty associated with the biopsychosocial model of illness. The expert is capable of being “Able to recognise, accept, explain and manage the uncertainty present in all aspects of rehabilitation, helping all people involved to understand and work with the patient despite the uncertainty.” This uncertainty arises from complexity, best defined as the presence of multifactorial, non-linear relationships between different factors, such that the outcome of changing one item upon another item often cannot be predicted accurately. For example, the effect of recommending progressive resistive exercise of the legs upon a patient’s walking endurance cannot be predicted with certainty because factors such as motivation, concentration, associated sensory functions, the availability of mobility aids, mood and fatigue may also all affect the outcome. The exercise itself may reduce fatigue and improve mood or may increase fatigue and cause pain, thus reducing motivation. Ethical considerations, legal considerations, and resource difficulties will influence the most complex cases. The expert in rehabilitation has to be able to negotiate all these issues and come to a justifiable course of action. A Mind-Map to look at while reading is below and can be downloaded here.

Complexity and uncertainty capability (5)

Table of Contents

The biopsychosocial model

Rehabilitation wishes to be holistic and to be patient-centred. Satisfying these wishes requires the use of the biopsychosocial model of illness. (here) It is the only available model that will fulfil both desires. Its central characteristics are:

  • it identifies an infinite range of factors which can influence the patient’s situation, grouped into eight domains in the version of the model used on this site;
  • the relationships between elements are
    • often non-linear
    • often bidirectional
    • often influenced by one or more other factors

These characteristics lead to (mathematical) complexity, and the features of complexity are:

  • identifying causal links is rarely easy and often impossible
  • predicting the influence of changing one factor is usually tricky and uncertain

Therefore it is hardly surprising that rehabilitation must manage uncertainty in almost all spheres. The surprise is how many predictions can be made.

The complexity and uncertainty vary according to the outcome one is considering. If one is considering whether a 25-year-old woman whose leg was amputated below the knee following direct trauma, with no other injury, will walk with a prosthesis, then the prediction is effortless (yes). But suppose one is considering whether she can return to work or previous leisure pursuits and maintain social networks. In that case, there are many more imponderable factors to consider, including her ability to adapt.

Uncertainty within the rehabilitation process

It is important to remember that rehabilitation is a problem-solving process, and many problems faced by people and organisations are solved by ‘trial and error’; a possible solution is tried, and if not successful enough, another solution will be tried. Prediction is difficult in most areas of life outside healthcare. The Covid-19 pandemic has demonstrated that, but predicting the cost of a large project is also too complex for a government to achieve.

Sometimes it is known that a solution might work, but the only way to know is to try it. If the problem is to reduce the chances of some specific event happening, and if the event is random and not very frequent, then it may take time (and careful analysis) to know if an intervention is helping. Last, if the outcome of interest is subject to considerable fluctuation, then detailed measurement and analysis may be needed to detect benefit, harm, or no effect.

Therefore, when considering rehabilitation, practitioners, patients, family members and funders all need to understand that trials of treatments are an essential part of all rehabilitation (and end-of-life care) and that outcomes often cannot be predicted with any certainty. Sometimes the likelihood of success can be estimated.

Trial of interventions

The most important consequence for the rehabilitation team, and for the individual members of that team, is that while it is often essential to start a trial of a possible treatment, it is even more critical to stop a treatment when it is not succeeding sufficiently to justify its continuation. In practical terms, this requires:

  • identification of a measurable outcome that is the target
  • agreement by both the patient (and family) and the team on
    • how long a reasonable trial should be
    • what constitutes a sufficient change to warrant the continuation
    • that treatment will stop if treatment fails
  • discussion of options to be considered if treatment fails

A trial should only start if these five requirements have been met. Kendall Downer and colleagues put forward a helpful mnemonic, TIME, in an article about setting up time-limited treatment trials.  It will be (a) difficult to know if success is achieved and (b) difficult to stop even if not succeeding because no plan exists, and hope will drive continuation. Articles discussing time-limited treatment trials are available here and here.

In summary, using the biopsychosocial model of illness inevitably leads to challenges, particularly when considering higher-level functional and social outcomes. As rehabilitation is a problem-solving process, the only practical way of handling these challenges is to offer structured trials of treatments with clear rules governing stopping. This is fair to the patient, who has an opportunity to benefit, and to others, as resources will not be used pursuing treatments that are not helping a patient.


The attitudes needed for this capability are:

  • curiosity, always asking others what they think
  • humility, being able to admit limited certainty without embarrassment
  • self-confidence, sufficient to feel able to admit the limits of your knowledge
  • flexibility, being able to change a decision in the light of new information
  • being decisive, being able to decide rather than paralysed by not knowing


The professional needs considerable self-confidence to show the required behaviours because both patients and the professional wish to feel confident. It is uncomfortable to admit doubt and that you cannot give certainty. This discomfort can be lessened considerably using the trial requirements outlined above. Setting out a plan with ‘what if’ already covered makes the professional feel in control and the patient feel that there is a path to follow, even if the exact route is uncertain.

For this capability, the professional:

  • acknowledges the level of uncertainty present in all formulations and decisions. This help both the professional and the patient to accept that doubt is the normal state of affairs, identifies the significant factors that are contributing to the certain predictions,
  • puts reasonable bounds around the range of uncertainty, avoiding the temptation to be overly optimistic at the better end;
  • explicitly identifies the major factors contributing to the uncertainty;
  • uses formal trials of treatment to reduce tension and to satisfy everyone that reasonable possible interventions have been tried;
  • makes decisions despite the irresolvable uncertainty, and does not either avoid making the decision or pass it over to anyone with less expertise;
  • formally documents in the clinical record the tension, the factors causing it, and the reasoning for the decision;
  • explains to the patient and family the uncertainty, the factors driving it, and the reason for the decision;
  • considers the legal and ethical aspects of the situation in any very complicated and challenging case;
  • seeks advice and help from team members, professional colleagues, and external experts when needed, delaying deciding to do so.

Two common themes underlie these behaviours.

The first is that the professional is simply being more considered and careful in making a more difficult decision. These behaviours are similar to those applied when making any decision, but they must be exaggerated.

The second is that the profession prepares both him- or herself by normalising uncertainty, pointing out uncertainties at every opportunity so that this is only different in extent. Suppose all professionals within the team undertake this approach. Patients and families will also feel that it is normal, just a little larger than usual.

Knowledge and skills

Managing complexity and uncertainty depend more upon skill than knowledge; knowledge tends to simplify complex situations and improve the accuracy of predictions.

However, the professional should be aware of what is known or discoverable. In other words, the professional must distinguish between managing uncertainty, where that certainty can be reduced through further investigation or through taking time to find the information and genuine uncertainty, where further research or searching will not materially reduce the tension.

Therefore the professional does need extensive general clinical knowledge, particularly of what is knowable – and how to discover that information. This will reassure the professional personally and others that there is genuine uncertainty rather than the individual being uncertain through ignorance.

The other knowledge class is personally acquired knowledge, referred to as experience. A professional needs to be able to evaluate their own experience and to be able to judge how dependable it is as a guide when applied to the current situation.

Thus the expert rehabilitation professional should know the following:

  • what is known, even if they do not realise it for themselves, and how to find the detailed information;
  • what they have learned from their own experience, and how to judge its validity;
  • the factors that determine prognosis, both in general across most situations and any particular prognostic factors for common conditions;
  • the legal framework appertaining to managing risks such as preserving the safety of a vulnerable adult;
  • an ethical framework or approach to use in complex, uncertain cases;
  • when and how to seek advice from others.

The skills needed are similar to those required in day-to-day practice, except they are needed at a higher level and must be maintained under stress.

Thus the primary, overarching skill needed is to maintain an entirely professional approach, using all knowledge and skills, in situations that can be challenging, stressful and often emotional.

The other skills that an expert rehabilitation professional needs are to be able to:

  • use the knowledge they have acquired through experience appropriately;
  • formulate a case thoroughly, including when relevant all legal and ethical aspects;
  • use trials of treatment effectively as a way to reduce uncertainty;
  • explain clearly and logically the facts used, the analysis and reasoning undertaken, and the decision;
  • accept, respect and listen to contrary views and/or new information;
  • modify a formulation, and change a decision in the light of new information or suggest further analysis and reasoning when appropriate.


In summary, the capability is demonstrating an ability to perform rehabilitation at the highest professional level under circumstances that can be challenging and stressful in many ways: personally, intellectually, emotionally, and inter-personally. A Mind-Map summarising it is given below and can be downloaded here. It requires considerable insight into the limits of the person’s knowledge and the value of their strengths and experience. When successfully applied, it can transform a situation. But often, transformational success is not possible. The goal should be establishing stability and understanding for all concerned, recognising that the problem is as it is and that the plan proposed is the least unsatisfactory solution.


Subscribe to Blog

Enter your email address to receive an email each time a new blog post is published. 
Then press the black ‘Subscribe’ button.

Exit mobile version