Rehabilitation is a problem-solving process. The first stage in any problem-solving process is to understand the problem in detail: what is the fundamental difficulty, which may or may not be the same as the initially identified problem; what are the important factors related to the genesis and/or maintenance of the problem; what will happen if we take no action; what factors if any might help identify actions that could improve the situation; and what factors help decide which actions should be undertaken and/or should not be undertaken? This is the process of reaching a formulation, a detailed analysis of a situation that includes both a description and an explanation. Formulation also includes a bridge to the next section, rehabilitation planning and interventions, and therefore includes collection of information about prognosis and information that will help in deciding between options.

Two quotations emphasise the need for formulation, and not only in psychiatry and rehabilitation. The second one refers to the formulation as a ‘compass‘. I think it would be more accurately described as a ‘map of the journey‘, showing where the person is, how the person arrived at their current location, and the possible routes for moving on. The map also provides information on obstacles, places to pick up help, eat or refuel, and so on. The compass is provided by the patient, and is operationalised in the form of long-term goals. An outline of the process of formulation is shown in this drawing. (here)

Ask not what disease the person has, but rather what person the disease has.”

William Osler (1849-1919)

The psychiatric formulation is the clinician’s compass guiding treatment. It should accurately reflect the patient and his or her pattern of functioning as well as the precipitants, predisposing and perpetuating factors, and prognosis, while also being clear, concise and clinically useful.

Len Sperry 1992 (here).

What is a formulation?

A formulation is the end-product of the assessment phase of the rehabilitation process. It is the foundation on which plans are built. It depends upon the appropriate data being collected and the analysis of those data being correct. If the formulation is inadequate or actually incorrect, the subsequent actions are likely to fail, to waste resources, and even be harmful.

A formulation is the explicit, formal exposition of:

  • what the presenting problem is, and
    • what other problems there are;
  • what the history and causes of these problems are, and
    • what factors are exacerbating or maintaining the problems;
  • what the prognosis is, treated and untreated, and
    • what actions might help in resolving the problem.

A formulation will also usually include, as it is relevant to the selection and planning of actions, information about:

  • what the patient’s over-arching goal and interests are, and
  • the availability of resources to help.

Despite its importance, formulation is rarely mentioned in the rehabilitation literature. Searching Medline (rehabilitation, formulation, case) identified 28 papers, of which 2-3 referred to case formulation. These papers came from psychiatry or psychology, and related to individual cases. I cannot recall reading about formulation in the context of rehabilitation, nor can I recall any teaching or academic or clinical discussion.

The process of formulation is important within psychiatry (e.g. see here), and much psychiatric practice is based on the biopsychosocial model of illness. Rehabilitation is also based on the biopsychosocial model of illness, and it also needs to develop a full, holistic understanding of the patient’s situation. Therefore it seems sensible to use the system of formulation widely used for decades in psychiatry.

In summary, a formulation is a concise synthesis of all the available information that should give the recipient a good understanding of the clinical situation: the nature of the problems; their genesis and causation; and their prognosis and the alleviating actions possible. It is based on the biopsychosocial model of illness

How to do it.

There are many articles and websites on undertaking formulation within psychiatry, and within most there is a reference to “The X Ps” where X is any number between 3 and seven. (for example here or here). The letter ‘p’ may stand for:

  • presenting problem
  • pattern (of symptoms I assume)
  • predisposing factors
  • precipitating factors
  • perpetuating (maintaining) factors
  • protective factors
  • prognosis
  • plan

The meanings attached to the letter p has grown like Topsy, just as the meaning attached to each letter of SMART, the widely used acronym in goal setting, has grown. (Over 113 different words for SMART; see here)

One approach (e.g. here) is to construct a table with the chosen ‘p’ words on the left-hand side, identifying the rows, and (in psychiatry) three columns for biological, psychological, and social factors. Some tables additionally include prompts, or even items that you can circle or highlight if present. In my view this devalues the formulation, because it removes most thinking and analysis.

There are many other approaches used in clinical reasoning (see here). From the perspective of a formulation, the most important consideration is that the clinician ends up with a comprehensive formulation that does not omit any important information. Whatever method is used, it is unlikely to be helped by trying to fill in a table while actually engaged in the diagnostic process of reaching a formulation.

On the other hand, the ideas or implicit questions that lead to the construction of a table may help in two ways. They may suggest hypotheses that have not already been thought of. They will also help organise and record the information collected.

Each clinician will develop and use their own detailed approach to the collection and analysis of data, and other methods are discussed elsewhere on this website (here and here). The important skill is to ensure that each domain of the biopsychosocial model is considered at some point, both when collecting the data and when constructing the formulation. The flow of information is illustrated in this drawing (here).

Recording the formulation

The formulation is the bedrock on which all plans are built. It is essential to have a record of that formulation so that anyone and everyone involved can assure themselves that it is sound, and that the actions they are expected to undertake are indeed appropriate and likely to benefit the patient. No-one should be expected to act simply because another (more senior or powerful) person says so. The need to provide a good justification for actions extends to the patient and family; they must have a clear formulation given to them.

Many important consequences flow from the proper formal recording of a formulation, written and accessible.

Forces commitment.
Coming to a diagnostic conclusion and making a firm decision is difficult in rehabilitation, because there are many unknowns and uncertainties. One common way to handle this is to speak in relatively vague generalities, without actually committing to any specific formulation. The clinician can then adapt their formulation at a later stage without having to acknowledge that it was incorrect.

This lack of commitment means that, unfortunately, the clinician learns less because he or she never actually has to acknowledge that a formulation was incorrect. Failures are often associated with good learning, and improved quality of practice.

Conversely, having to commit to something in writing will generally make the clinician (or the clinical team) more careful and thoughtful. For example, the clinician may well double-check the quality of a piece of important information that is crucial, or ensure that information from all domains of the biopsychosocial model has been considered.

Documents facts and reasoning.
One major difficulty faced, when reviewing rehabilitation records, is to know what the situation was. The nature of the goals give clues – if a goal is to walk further, it implies that the patient is walking – and incidental comments may give other clues, but base facts are often not recorded. The reason is simple. Everyone involved at the time knows, and feels it is not necessary to record this information.

A second difficulty is to understand why certain actions were taken or goals were set, while other actions or goals are not mentioned. There is rarely any explicit justification for interventions, even interventions that carry significant risk or use significant resources.

Improves continuity.
Most patients have long-term problems, and over a few months there will often be many changes in team composition, and responsibility will pass not only from person to person but also team to team and organisation to organisation. A well-written formulation will reduce risk of harm to the patient, and make it more likely that a consistent approach is taken across settings and over time.

Improves patient and family understanding and trust.
When patients and families have a situation explained, they will usually forget most of in, and misinterpret the remainder. That is entirely normal. Furthermore, clinicians giving information tend always to err on the side of optimism or omission, not being entirely straightforward. Probably mistakenly, clinicians feel that patients do not want to have the full truth.

However, if the patient sees the written formulation used by the team, they will be reassured to know that what they were told was what everyone is using, which gives much greater confidence in the information given to them.

Thirdly, sometimes the patient or family will point out errors in the formulation, perhaps disclosing new information, or reminding the clinical team about information given.

The format of the formulation is a matter for the team to decide. Nonetheless, it is unlikely to be helpful if it is just a table; it will be much less useful if it uses jargon or abbreviations ; and if it is handwritten it may not be legible.

Therefore it should be well-written, using plain English (translated if necessary in equally straightforward terms), with a clear logical structure. It also needs to be succinct. A formulation of more than one page is probably too long, and many good formulations will be much less. Seeking feedback from patients and others will improve the recording of formulations.


Everyone will have a formulation of the patient’s situation as soon as they meet. It is their understanding of the case. However internal, explanatory formulations are often incomplete, sometimes wrong, and are not subject to any critical evaluation.

Sound rehabilitation plans depend totally on a full understanding of the situation; the term used here is a formulation. This in turn depends upon an appropriate assessment, data-collection process. Having a consistent way to develop a formulation, and then to present and record the formulation, will improve the quality of rehabilitation.

This page has outlined some of the characteristics of a good formulation. One analogy is to consider a formulation as a map. The map shows how and why a patient has arrived at his current location, including showing places (events) passed through and difficulties overcome. In this analogy, the vehicle the patient is travelling in is determined by the disabilities, which will limit the routes available. But the map will show some possible routes the patient could take, to move on. Which route is taken will depend upon the patients preferred reachable destination.


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