Capability 5: complexity and uncertainty
Last updated: June 3, 2025
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. 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. For example, the effect of recommending progressive resistive exercise for the legs on a patient’s walking endurance cannot be predicted with certainty, as factors such as motivation, concentration, associated sensory functions, the availability of mobility aids, mood, and fatigue may also influence the outcome. The exercise itself may reduce fatigue and improve mood, or may increase fatigue and cause pain, for example, in a knee with osteoarthritic changes, thus decreasing motivation. Ethical considerations, legal considerations, and resource difficulties will influence most cases. The expert in rehabilitation must be able to navigate all these issues and arrive at a justifiable course of action. Some key knowledge and skills, as well as behaviours indicative of capability, are summarised in the Mind-Map below.
Table of Contents
The capability
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.”
Introduction
Rehabilitation involves people, professionals, the individual, their family and friends, and others. Unless the rehabilitation episode concerns a minor, straightforward matter resolved after assessment by giving advice and possibly a brief intervention, the process inevitably involves uncertainty, different perspectives and priorities among various parties, and often issues concerning resources, legal, and ethical matters. The temptation is not to find or acknowledge them, convincing yourself or your team that “we are only concerned with rehabilitation and those matters are not our concern”. This approach does you and your patient a disservice, may lead to harm, and may occasionally be considered a failure to uphold professional standards.
This is not to suggest that rehabilitation professionals or teams should attempt to resolve the complex issues on their own. Many issues have no satisfactory solutions, and most problems involve other organisations or individuals, but the professional must identify and make explicit the complex and potentially challenging issues. Doing so will often lead to significant improvement in outcome, because exposing the challenge allows others, who may have been afraid to mention the problem, to become involved and help in managing the uncertainty.
The key characteristic of an expert with this capability is that they will always admit their uncertainty and never feel embarrassed about asking others, including patients and families, for their help and opinion.
The cause: the biopsychosocial model
Rehabilitation wishes to be holistic and patient-centred. Satisfying these wishes requires the use of the biopsychosocial model of illness. 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 specific causal links is rarely easy and often impossible
- predicting the influence of changing one factor is usually tricky and uncertain
- Most individual factors:
- Are influenced by several other factors
- Influence several other factors
- Combinations often have additional effects
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 being considered. Suppose 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. In that case, 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, and prediction is challenging.
Managing treatment uncertainty
It is essential to remember that rehabilitation is a problem-solving process, and many problems faced by people and organisations are solved through a process of ‘trial and error’; a possible solution is tried, and if it is not successful enough, another solution is attempted. Prediction is difficult in most areas of life outside healthcare.
Sometimes it is known that a solution might work, but the only way to discover if it does help is to try it. If the goal is to reduce the likelihood of a specific event occurring, and if the event is random and infrequent, then it may take time (and careful analysis) to determine if an intervention is effective. This poses a huge problem when managing epilepsy. 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 also in end-of-life care), and that outcomes often cannot be predicted with certainty. Sometimes the likelihood of success can be estimated.
Trial of interventions
The most important consequence for the rehabilitation team is that, while it is often essential to initiate a trial of a possible treatment, it is even more critical to discontinue a treatment when it is not sufficiently effective to justify its continuation.
In practical terms, this requires:
- Identifying an agreed-upon measurable target outcome
- 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. Without a prospective plan accepted by all, it will be difficult to determine if success is achieved and to stop if failing; because no further action is planned, hope will drive continuation. Articles discussing time-limited treatment trials in intensive care are available here and here; the principles outlined therein are likely to apply in rehabilitation.
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.
Managing prognostic uncertainty.
The difficulty in predicting the effect of an intervention is part of a broader challenge in giving a prognosis. Prognosis is uncertain in most situations, including when someone is recovering from an acute event, has a fluctuating condition or a progressing disorder, or even appears stable. For example, if someone who has had multiple sclerosis for five years and has recently developed mild gait disturbance, do you recommend they should consider a wheelchair adapted house?
This challenge is exacerbated by the loose use of ambiguous words, such as ‘recovery’ or ‘walking’, where patients and professionals typically have widely different interpretations. I have discussed the difficulties associated with recovery in a blog post, ‘Recuperation, recovery, and rehabilitation.’
Thus, the first step is to discuss prognosis using unambiguous terms and examples, usually functional. Avoid phrases like ‘getting better’. Instead say “In three months, you should be able to walk without support but slowly, needing a stick, and not over rough ground.”
Uncertainty is often translated into, “Well, we can never be certain” with an implication that even the most improbable futures may occur. For example, a man who cannot stand eight months after a stroke might say his goal is to walk along the Cornish coast path for 15 miles at a commemoration event in 15 months’ time. The temptation is not to say that the goal is unachievable by saying, “I think it is unlikely, but you never know.” This leaves open and unrealistic hope.
A common challenge to me concerns people with a prolonged disorder of consciousness, where I will often have to explain that the patient will never regain consciousness. Families frequently say that I cannot be 100% certain, miracles occur, or they found a case on the internet where recovery occurred after ten years.
I will usually admit the philosophical truth that I cannot know the future but then qualify that statement by putting bounds around my prediction. I frame my prediction as the most likely range of possibilities, the best plausible outcome, and the worst outcome. If they ask for percentage likelihood, I translate it into the middle 80%, with the extreme best being less than 1%
In most circumstances, one should also stress that the prediction does not imply that we will act to stop a better recovery by emphasising that you will provide more input if your prediction is too pessimistic. You should acknowledge their hope but say you will act on your prediction to make progress now.
In summary, when discussing prognosis, you should:
- Use unambiguous functional terms
- Acknowledge uncertainty but frame it in terms of most likely, best, and worst outcomes
- Acknowledge their hope but emphasise need to act now on the most likely, stressing that if you are wrong, you will continue to provide necessary input
- Make it clear that you do not agree with any impossible hope, but you understand and respect their hope.
Managing ethical and legal matters.
This covers a huge range of issues, and experience in recognising and managing them is the only way to learn and improve.
In rehabilitation, the most significant issues are:
- The Mental Capacity Act and identifying when people cannot make decisions, documenting it, and handling decisions correctly
- Vulnerability and safeguarding
- Different opinions, priorities, and decisions between the patient and others – family, professionals, agencies etc
- Lack of resources, especially when a known effective intervention is available to some people
The essential expertise is to:
- Identify and explicitly acknowledge the issue
- Discuss openly with all parties
- Obtain help and information from others
- Document your decisions, giving the factors considered and the reasons for the decision
Attitudes
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 being paralysed by not knowing
Behaviours
The professional needs considerable self-confidence to exhibit the required behaviours, as patients need to trust professionals and professionals 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 professional prepares themselves by normalising uncertainty, pointing out uncertainties at every opportunity, so that this is only different in extent. If the team’s culture is to embrace uncertainty at all times, patients and families will also feel that it is normal so, when a much more challenging complex issue arises, they will not be shocked by open discussion of uncertainty.
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 certainty can be reduced through further investigation or by taking the time to gather information, and genuine uncertainty, where additional 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 due to ignorance.
The other type of knowledge is personally acquired knowledge, commonly referred to as experience. A professional needs to be able to evaluate their own experience and 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 prognostic factors for common conditions;
- the legal framework pertaining 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 required are similar to those needed in day-to-day practice, except they must be applied at a higher level and maintained under stress.
Thus, the primary, overarching skill needed is to maintain a completely professional approach, utilising 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 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.
Conclusion
In summary, the capability demonstrates an ability to perform rehabilitation at the highest professional level under circumstances that can be challenging and stressful in multiple ways: personally, intellectually, emotionally, and interpersonally. 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. However, transformational success is often not possible. The goal should be to establish stability and understanding for all concerned, recognising that the problem is as it is and that the proposed plan is the least unsatisfactory solution. Documenting your decisions is essential because often doing so draws attention to matters you have overlooked and helps your reasoning; it is also invaluable when someone challenges your decision later!