Resource-to-result ratio

The recent NICE guidance on stroke rehabilitation suggests each person should be “offered needs-based rehabilitation … This should be for at least 3 hours a day, on at least 5 days of the week.” This focus on the dose of rehabilitation reflects a reliance on a biomedical theory of health where interventions influence specific problems in a dose-dependent way. Is this the correct approach to rehabilitation? The guidance includes a slight ambiguity, as it says rehabilitation should “… cover a range of multidisciplinary therapy …” without defining therapy. The guidance recognises implicitly that the team needs to assess and plan goals, liaise with others, etc., but does not indicate whether these crucial activities are included in the time. Moreover, professionals must write notes, talk to family members, respond to the patient’s questions, and undertake many other activities that are part of the person’s rehabilitation.

Reliance on the biomedical theory of healthcare has led to the inappropriate quantification of rehabilitation without appreciating that parts of biomedical care, such as surgery, would not be appropriately quantified using time. This page explores rehabilitation content, using the general rehabilitation theory to analyse it. I conclude that quantifying rehabilitation is usually inappropriate and that therapy is a vague and imprecise term, so it should not be quantified.

Table of Contents

Rehabilitation resource-to-result ratio


People referred to the black box of rehabilitation from about 1970 (Organizing therapeutic work of OT and PT in stroke rehabilitation units: opening the “black box” of organisational issues. Koen Putman et al., journal not known), and researchers have struggled to define what is ‘inside the black box’. The black box was also referred to in psychiatric rehabilitation.

One group has worked for ten or more years to develop the Rehabilitation Treatment Specification System, a detailed method for describing an intervention that has three axes: the target, which is usually selected from the World Health Organisation’s International Classification of Functioning (WHO ICF); the ingredients of the intervention, specific actions, equipment, etc; and the theory justifying or explaining how it should work.

A multicentre group of spinal cord injury rehabilitation services developed and published a Classification of Spinal Cord Injury Rehabilitation Treatments. Julie Gassaway and her colleagues developed a descriptive taxonomy for use within an electronic patient record. Seven papers published covered most of the observed interventions in the participating centres. Rebecca Ozelie and colleagues described the taxonomy for use by occupational therapists. The published paper shows how much detail was collected.

Tammy Hoffmann and colleagues developed a generic system for describing complex treatments when reporting controlled clinical trials or other research into a complex treatment.  The systematic approach described in their paper, Better reporting of interventions: template for intervention description and replication (TIDieR) checklist and guide, is widely used.

Jeremy Howick and colleagues published a similar checklist for describing placebo drugs in controlled trials, reminding us that the description of each group in a controlled trial of rehabilitation should be of an equal standard. These descriptions include a rationale as well as the main aspects. The TIDieR framework has been used in many descriptions of rehabilitation interventions published in Clinical Rehabilitation.

Before you become too enthusiastic about these various descriptions of rehabilitation interventions, please read “A rehabilitation intervention to promote physical recovery following intensive care: a detailed description of construct development, rationale and content together with proposed taxonomy to capture processes in a randomised controlled trial.” You will find an eighteen-page article, where five whole pages are filled with a complex table listing the interventions being studied. Their description followed Mary Taylor’s and her colleagues’ advice, who felt that “intervention description is not enough.”

Analysis of the problem.

The challenge of quantifying and describing the rehabilitation resource given to someone is exacerbated significantly by the loose and inconsistent use of terms and a lack of clarity about the concepts being used.

Rehabilitation is a broad term representing the entire process from first contact with a patient to final discharge. Quantifying it by time is meaningless because the processes and the outputs cover a vast range from undertaking several days of inpatient assessment, observing patterns of behaviour and producing a formulation for a person with challenging behaviour after hypoxic brain damage to injecting a muscle with botulinum toxin for spasticity. Any reference to rehabilitation must be interpreted as applying to the complete process.

Therapy is equally ambiguous. It might refer to:

  • A person, the therapist and what they do. If so, it must include, on a smaller scale, the whole process of rehabilitation and, additionally, any other associated professional activities such as continuing professional development,
  • The time the therapist spends in direct contact with a patient, If so, it will include assessment, formulation, giving advice and support, training an activity, etc., but it will exclude talking to family members, arranging handover to another service, attending goal-setting meetings etc.,
  • Only the time a therapist devotes to training and practising an activity.

Third, there is a conflation of description with categorisation, with most classification systems being detailed descriptions not based on any firm underlying principles.

Last, and most importantly, all descriptions and attempts at categorisation of therapeutic input are based on unfounded assumptions about the effective component of a highly complex intervention.

For example, when a therapist assesses a patient, gives a formulation, and starts a treatment programme to improve mobility, the description will focus on the training programme. However, it is equally likely that other parts of this process will lead to measurable benefits, such as:

  • factual information about the situation and its prognosis,
  • emotional support facilitating the person’s return of confidence and emotional stability,
  • practical support, for example, providing a walking aid or arranging transport for the person’s disabled partner to visit,
  • the enthusiasm and personality of the therapist,
  • resolving some unrelated worries, such as the person’s belief they will die within six months of their stroke.

We will likely overlook essential aspects of the rehabilitation process in our drive to describe some parts; we will explain and evaluate what we can describe rather than what is crucial. Indeed, the whole process, rather than any one item, may lead to the benefit. Rehabilitation may be the ultimate bundle of care. The observed characteristics of stroke rehabilitation unit care would explain how stroke rehabilitation units reduce mortality.

The general theory of rehabilitation suggests rehabilitation facilitates adaptation rather than specifically retraining a person. Catalysis is not a dose-dependent phenomenon, nor is the catalyst easily associated with its effect. We are likely to overlook many catalytic benefits.

To summarise, we have evidence that rehabilitation, as a process, benefits patients. We have assumptions about which parts of the complex process help and theories to support a small minority of those parts, which we describe in detail. However, the benefit may arise from the whole package and not from any limited number of its components, and aspects we have yet to consider may play a vital role in the process.

This is not to disparage attempts to understand and describe what we do. It reminds us that we cannot assume we are defining and measuring all rehabilitation’s relevant, beneficial aspects.

The general theory’s classification.

The general theory of rehabilitation offers a new way to think about rehabilitation interventions, and I will explore it here.

The hypothesis is that rehabilitation facilitates a person’s adaptation to illness. Adaptation to illness occurs in several ways:

  • regaining performance on activities limited by the illness
    • undertaken by the same means as originally
    • undertaken in new ways
  • learning new activities that allow the person to meet their needs and life goals
    • replacing previous activities
    • completely new, usually associated with new life goals
  • Altering their needs/life goals
    • Maintaining similar goals but expecting a lower level
    • Altering their goals within the person’s system of values

Rehabilitation may assist the person in many ways:

  1. Providing information for the person to use
    1. An explanation of the causative factors and mechanisms
    2. A prognosis coupled usually with advice on actions and changes that may help
  • A more detailed plan, including resources that might assist
  1. Undertaking some specific activities on a one-off basis, such as
    1. Making formal referrals to other people or organisations, especially to meet care needs
    2. Advising on and providing aids, equipment, and adaptations
  2. Direct assistance in changing goals or developing new goals
  3. Direct assistance in relearning activities or learning new activities safely
    1. Including practising until it is safe to do so unaided
  4. Direct assistance in learning self-management skills
  5. Direct assistance in psychological and personal adaptation (i.e. coping)
  6. Indirect assistance, supporting the family
    1. With information, teaching care skills, assisting the patient’s self-management
    2. Emotionally
  7. Indirect assistance, supporting other involved people or agencies
    1. With information, teaching care skills, assisting the patient’s self-management
    2. E.g. employers, care staff, charities, benefits agencies

These types of assistance fall into three groups;

  1. Catalytic (not dose-dependent) [a and b above]
    These activities will require resources, but their effects are not proportional to the resources needed or given to them. If done to a lower standard due to inadequate resources, they will likely have no effect, which is a waste; more importantly, there is a significant chance that a low-standard intervention may cause harm.
  2. Direct assistance (some association between dose and effect)
    These rehabilitation activities are directly concerned with the patient. There will be a relationship between the amount and the effect, but this will be influenced by other factors, including how much the person practices between teaching sessions. There will always be a gradual lessening before the withdrawal of the activity to continue guidance.

    Insufficient resources may lead to harm, for example, starting a patient walking and withdrawing before safety is confirmed. Inadequate resources, where the rehabilitation person or team has insufficient expertise, is a crucial part of the ‘dose’; hours of low expertise input is wasteful and probably harmful.

  3. Indirect assistance (some association between dose and effect)
    These rehabilitation activities are only indirectly concerned with the patient, though there will usually be some benefit for the patient, such as carers providing safe rather than unsafe care.

Thus, the general theory of rehabilitation starts to clarify what rehabilitation does so that any quantification can be interpreted and used appropriately.

Resource quantification.

The general theory of rehabilitation suggests interventions fall into three general classes:

  • Catalytic, with no link between resource used and effects seen,
  • Assistive (direct or indirect) teaching or training, with a definite but not firm association between resources used and effects seen,
  • Mixed, combining catalytic and assistive.

It also emphasises that the person’s input is vital, and the extent of this contribution, for example, by practising an activity independently, will significantly impact the measured outcome.

Quantification must use a metric appropriate to the intervention and its purpose. For example, no one would quantify surgical operations by the time spent. An operation is a whole and can only be counted when it has achieved its purpose, such as replacing an arthritic hip with a prosthetic hip. On the other hand, it is reasonable to measure exercise or practice by the time devoted because there is a correlation between time and effect.

In rehabilitation, completing an assessment and accompanying formulation is a single unit; half of an assessment or formulation is not helpful and may cause harm. Similarly, getting and adjusting a piece of equipment for a person is a unitary activity that time cannot quantify.  Of course, the resources devoted to a unitary activity can be measured, and one can consider whether fewer or more resources might be needed in general. Still, for an individual patient, only the output can be counted.

In general, any catalytic activity should be quantified as a unitary activity. Examples include assessment and formulation, planning a course of action, providing equipment, arranging adaptations to physical structures, and, arguably, teaching self-management. However, the extent of benefit from teaching self-management depends upon the resources devoted to it.

Many other interventions will have an element of increased effect with increased resources, though the correlation will vary. These can be quantified, but quantification needs to be appropriate.

The effectiveness of most interventions is proportional to the expertise of the professional; the more expert, the better the outcome. For larger-scale activities, the expertise involves an appropriate range of professions. For example, a five-day inpatient stay in a unit where the team only includes nurses, physiotherapists, and occupational therapists will be much less effective than five days with additional input from rehabilitation-trained doctors, clinical psychologists, social workers, and speech and language therapists.

However, once a treatment programme is in place, the patient can often practice without a professional. This depends on the environment for inpatients, including the availability of trained rehabilitation assistants who can provide support, supervision, and feedback. Crucially, the environment must be structured to facilitate practice in everyday activities such as dressing and using a toilet, and the culture must encourage independence and acceptance of risk.

The direct training of patients or family members combines catalytic and treatment functions, making quantification using time less informative. For example, it takes much longer to teach a person with poor attention, fatigue, and memory impairment than it does (for the same task) to teach someone without those obstacles.

No one would quantify one completed operation using time as the unit.  For example, some operations take longer if the patient has additional problems impacting the procedures. Limiting a surgeon to one hour would be unthinkable, asking them to stop halfway through if it needed to be completed.

In summary, quantifying the rehabilitation resource used is complex because:

  • There is no standard metric one can use for all rehabilitation activities,
  • The relation between resource and outcome is:
    • Nil when the rehabilitation input is a unitary, catalytic activity, or
    • Weak when the input is assistive. Even then, the variability between the responsiveness of patients is more considerable than the relationship between input and outcome.
  • Quantification by time given is only valid when measuring the amount of practice a patient undertakes, including when no therapist is present.

Synthesis. Resource-to-result ratio.

This exploration has been concerned with classifying rehabilitation interventions and how to quantify them so that we may target resources on activities that deliver the best improvement in outcome from the available resources. Despite extensive work by researchers, theoretically-based categorisation has yet to emerge. There are several methods for giving a detailed description of rehabilitation interventions. They are not feasible and only describe what the researcher feels is relevant from the many other parts of the intervention; they may overlook the vital aspects leading to benefit.

The general theory of rehabilitation suggests that many interventions are catalytic; these will not have a dose-response relationship with outcomes. Moreover, they are single units, comparable to a surgical operation, and can only be quantified as a unit. Other interventions may have a dose-response relationship but only as facilitating adaptation. Much rehabilitation involves learning to perform activities. The critical item to quantify is the total amount of practice undertaken by the patients, not only the time spent practising with a therapist.

It also highlights that the patient’s adaptation is the target, so the assets and deficits of the patient will determine how much resource is needed. Many patients will have problems with attention, mood, fatigue, and memory, all of which will impact the resources required.

Thus, while quantifying rehabilitation resources may be helpful, we cannot interpret or use the information to guide therapy until we have a much better understanding of what components of the rehabilitation process have the most effect. We use measures of resource at our peril because we may measure the wrong thing and misinterpret the results.


Observational cohort studies have failed to find any strong dose-response relationship between the amount of rehabilitation given, usually measured in time, and the extent of benefit on the measured outcome. The general theory of rehabilitation gives a new perspective on quantifying rehabilitation. Much rehabilitation is catalytic, where the appropriate metric is not time; instead, it is the completion of the activity. The best example is assessing a person and giving them an explanation, prognosis, and plan. Other rehabilitation activities should have some relationship, but this is weak mainly because patients vary significantly in their response to the input. The variability arises from the condition itself, for example, if it reduces attention and memory and from patient characteristics, such as a high level of motivation.

An additional difficulty arises from our ignorance of what aspect of the interaction between a patient and the team members involved has the most effect. For example, features such as the enthusiasm and empathy of therapists may have a more significant impact than any specific training. We should certainly continue to evaluate all aspects of the rehabilitation process. Still, we must remember that the whole process is beneficial, and until we have a better understanding of what is effective and why, we must be cautious when measuring resources.

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