Functional assessment in PBS for adult services: a practical guide

When you support adults in social care, you rarely need more reminders that behaviour is communication. What you do need is a practical way to work out why a behaviour is happening, what is keeping it going, and what to change first so that everyone is safer and life is better. That is where a functional assessment sits within positive behaviour support (PBS): it is the structured process that turns day-to-day observations into a clear explanation and an action plan that staff can actually follow.

This article explains what a functional assessment is in adult services, how it fits into PBS, and how to translate what you learn into proactive, skill-building supports. It is written for registered managers, team leaders, PBS leads, senior support workers, and anyone involved in creating or reviewing support plans.

What a functional assessment is (and what it is not)

A functional assessment is a methodical way of understanding what someone is getting or avoiding when a behaviour happens, and what makes that behaviour more likely on certain days, in certain places, or with certain people. In PBS, the point is not to label a person or to locate “the problem” inside them. The point is to build a shared, evidence-based understanding of the interaction between:

• the person’s needs, preferences, communication, and skills
• their environment, routines, demands, and relationships
• the immediate triggers and the responses that follow

NICE guideline NG11 on challenging behaviour and learning disabilities highlights the importance of understanding the cause of distressed behaviour and doing thorough assessments so steps can be taken to improve quality of life. NICE NG11

The NHS England PBS Competence Framework describes PBS as “a data-driven approach to decision making at every stage” and places “functional assessment to inform function-based intervention” at the heart of good practice. NHS England PBS Competence Framework

Common misconceptions to avoid

• “It’s just an ABC form.” ABC notes can be part of it, but functional assessment is wider: interviews, routine mapping, health checks, skills assessment, and pattern analysis.
• “It’s only for high-risk incidents.” The earlier you understand patterns, the more you can prevent escalation and reduce restrictive responses.
• “Once it’s written, it’s done.” Functional understanding needs revisiting when the person’s health, environment, or staffing changes.

How functional assessment fits into PBS in adult services

PBS is not a single technique. It is a framework for improving quality of life and reducing distressed behaviour through values-led, evidence-based, person-centred support. Functional assessment is the assessment stage that helps you move from “what happened?” to “what should we do next, and why?”

In adult social care, the functional assessment stage often sits alongside care planning, risk assessment, MCA/DoLS processes, clinical input, and multi-disciplinary reviews. It should connect, not compete, with existing safeguards and paperwork.

Three outputs you should expect from a good functional assessment

• A clear definition of the behaviour that everyone records in the same way (observable, measurable, no judgemental language).
• Patterns that show when the behaviour is more or less likely (time of day, task demands, certain settings, particular interactions).
• A testable hypothesis (a short “best guess” statement) about what the person is communicating or achieving via the behaviour.

Step-by-step: running a functional assessment that works in real services

Many providers get stuck because they attempt a perfect assessment rather than a useful one. The goal is a practical, defensible process that gathers enough data to make good decisions and then keeps learning over time.

1) Define the behaviour in plain, observable terms

Start by agreeing what counts as the behaviour and what does not. Avoid umbrella labels like “aggression” or “refusal”. Describe topography and impact, for example:

• “Hits staff with an open hand” rather than “violent”
• “Pushes items off the table and shouts” rather than “attention seeking”
• “Leaves the area when asked to shower” rather than “non-compliant”

This protects the person’s dignity and makes your data meaningful. It also helps staff feel more confident because they know exactly what to record.

2) Check for health, pain, and sensory factors early

Behaviour can change quickly when someone is in pain, unwell, sleep deprived, constipated, or experiencing sensory overload. In adult services, overlooked pain is common when communication is limited. A functional assessment should actively explore health and wellbeing factors, not treat them as an afterthought.

Practical actions include:

• reviewing recent GP contact, medication changes, and side effects
• tracking sleep, appetite, bowel patterns, and signs of discomfort
• checking hearing/vision needs, dental health, and mobility pain

CTA: If your team needs a consistent way to reduce escalation and keep people safe, explore Positive Behaviour Support training and build shared language across the service.

3) Gather background information that affects day-to-day coping

Functional assessment is stronger when it includes the “slow variables” that change someone’s coping capacity. Examples include bereavement, housing instability, changes in family contact, staffing changes, anniversaries, trauma reminders, or loss of valued activities.

Do not rely on paperwork alone. Ask people who know the person well (including the person themselves where possible) what a good day looks like, what predictably makes a day harder, and what support helps.

4) Collect direct data that can reveal patterns

In busy settings, data collection needs to be realistic. The NHS England PBS Competence Framework notes that assessment should include a baseline measure of current behavioural rate and intensity so you can take repeated measurements after changes to gauge impact. NHS England PBS Competence Framework

Choose one or two methods that staff can sustain:

• Frequency: how many times per shift/day/week
• Duration: how long episodes last
• Intensity: a simple 1 to 5 rating with examples
• ABC notes: what happened just before, what the behaviour looked like, what happened immediately after

Keep recording forms short, and make sure leaders review them routinely. Data that is collected but never used will quickly stop being collected.

5) Look for likely functions in adult services

Functional assessment usually considers whether behaviour is serving one or more of these purposes:

• Escape or avoidance: getting away from tasks, demands, noise, crowded spaces, or difficult interactions
• Access: obtaining preferred items, activities, or people
• Attention or interaction: gaining social connection, reassurance, or a response from others
• Sensory or regulation: meeting a sensory need, reducing discomfort, or regulating arousal

It is common for the same behaviour to have different functions in different contexts. For example, leaving the room might avoid a demand in one situation, but access quiet in another.

6) Write a hypothesis statement the whole team can use

A useful hypothesis is short and specific. It should link trigger, behaviour, and likely payoff. For example:

• “When staff ask X to stop a preferred activity with no warning, X shouts and pushes items. This tends to delay the transition and results in staff negotiating or offering alternatives. The behaviour may be helping X avoid sudden transitions and gain more control.”

Notice the language: it is descriptive, it avoids blame, and it gives you clear ideas for what to change.

Turning assessment into proactive supports (what to change first)

A functional assessment is only valuable if it improves support. The best plans are multi-component, but they are also prioritised. Start with the changes most likely to reduce distress quickly while building long-term skills.

1) Improve predictability and reduce unnecessary triggers

If assessment suggests that sudden change, unclear expectations, or high demand periods are key triggers, focus on predictability. Examples include:

• clear visual or written schedules where appropriate
• advance warnings before transitions
• task breakdown (smaller steps, shared starts, supported choices)
• planned access to valued activities so they are not constantly “won” through escalation

CTA: If your service is still relying on last-minute responses, consider skills-focused training such as Restraint Reduction training to strengthen prevention, de-escalation, and post-incident learning.

2) Teach a replacement skill that meets the same need

The person needs a more effective, safer way to get what the behaviour currently achieves. In adult services, replacement skills often include:

• requesting a break (verbally, with a card, or via an agreed gesture)
• asking for help before tasks feel overwhelming
• communicating discomfort or pain
• requesting time alone or reduced sensory input
• learning a coping routine (breathing, paced walking, use of sensory tools) that is respected by staff

Be explicit about how staff will prompt and reinforce the replacement skill. If the replacement skill is harder than the existing behaviour, it will not stick.

3) Align staff responses so the plan is consistent

Functional assessment often shows that staff responses accidentally reward escalation, even when staff are doing their best. For example, if shouting reliably leads to demands being removed, the behaviour may be strengthened over time.

Consistency does not mean rigidity. It means agreement. Leaders should coach staff to respond in ways that:

• protect safety and dignity
• avoid escalating confrontation
• do not unintentionally reward the behaviour you are trying to reduce
• actively teach and reinforce the replacement skill

4) Plan for the hardest moments: reactive strategies that reduce harm

Even with strong prevention, there will be times when someone is overwhelmed. Reactive strategies should focus on reducing harm, not on “winning” an interaction. They should be specific, agreed, and trained so staff are not improvising under pressure.

Where physical interventions are used, they must always be proportionate, lawful, and consistent with the person’s rights and your organisational policy. The NHS England PBS Competence Framework highlights measuring restrictive practices (including physical restraint) as an important outcome variable alongside other outcomes. NHS England PBS Competence Framework

CTA: If your team needs to build safer, more confident responses during high-risk incidents, see Physical Intervention training for staff who may need last-resort skills within a restraint reduction approach.

What good outcome measures look like (beyond incident counts)

Incident reduction matters, but a plan that reduces incidents by restricting a person’s life is not good PBS. The NHS England PBS Competence Framework emphasises that assessment should include baseline measures of quality of life and current usage of restrictive practices, such as physical restraint. NHS England PBS Competence Framework

Consider tracking a small set of outcomes that reflect a better life, such as:

• participation in chosen activities
• time spent engaged in meaningful routines
• successful use of the replacement skill
• reduction in restrictions, including fewer holds, less PRN use, and fewer exclusions from activities
• staff confidence and consistency (measured via brief checklists or coaching observations)

Functional assessment in adult services: practical examples

Example 1: “Refusal” that is really demand overload

A support team reports that a person “refuses personal care” and becomes distressed when prompted to shower. Data shows episodes cluster on days with community outings, when the person is already tired. Staff also notice that instructions are given quickly and repeatedly.

Hypothesis: personal care prompts are experienced as high demand when the person is already fatigued, and distress leads to tasks being delayed or cancelled.

Proactive supports: schedule personal care at a calmer time, reduce verbal load, offer a choice of two acceptable options, use a clear start cue, and teach a “break please” request that staff honour quickly.

Example 2: Distressed behaviour linked to loss of control

A person becomes distressed and throws items when staff end a preferred activity. ABC notes show the pattern is strongest when the ending is sudden and when there is no clear “what next”. Staff often attempt to calm things by offering extra minutes after the escalation.

Hypothesis: sudden endings reduce perceived control; escalation delays the transition and sometimes gains more time.

Proactive supports: predictable countdown, a consistent transition routine, planned “finish and choose” opportunities, reinforcement for moving on calmly, and staff agreement not to extend time only after escalation.

Example 3: Escalation during busy communal times

A person becomes distressed during mealtimes and may hit out if approached. Notes show it happens more often when the dining area is noisy and crowded, and when staff stand close behind them.

Hypothesis: sensory overload and personal space invasion trigger distress; hitting creates distance and reduces the immediate sensory input.

Proactive supports: quieter seating, fewer people nearby, agreed approach from the side, offering noise reduction options, and teaching a clear “space” signal that staff respond to quickly.

Governance: keeping functional assessment ethical, lawful, and person-centred

In adult services, functional assessment must sit within robust safeguarding and rights-based practice. Key points include:

• Capacity and consent: involve the person as much as possible, use accessible formats, and follow MCA processes where needed.
• Co-production: include family (where appropriate), advocates, and the multi-disciplinary team.
• Least restrictive practice: aim to reduce restriction and increase choice and participation over time.
• Staff competence: ensure staff are trained to record data, follow plans, and reflect after incidents.

If you support children and young people as well as adults, you may find our training for children’s services useful for aligning approaches across age groups and settings.

FAQ

How long should a functional assessment take in adult social care?

It depends on risk and complexity. Some questions can be clarified quickly with focused data collection and staff interviews, while complex patterns may require longer observation and specialist input. The key is to collect enough information to form and test a clear hypothesis, then keep monitoring as support changes.

Who should lead a functional assessment?

Ideally, someone with PBS competence and experience in functional assessment leads, but it should never be done in isolation. It works best when the wider staff team, the person, and the multi-disciplinary team contribute observations and agree what changes will be tested.

What if there seems to be more than one function?

That is common. You can write more than one hypothesis or describe how the function changes by context. The important thing is to make each hypothesis specific enough that it suggests clear proactive strategies and measurable outcomes.

Is functional assessment only about stopping incidents?

No. A high-quality functional assessment should lead to supports that improve day-to-day life, communication, choice, and participation. Incident reduction is important, but it should be achieved through better support rather than increased restriction.

How do we know if our plan is working?

Use baseline measures (for example frequency and intensity) and review them routinely after changes. Track quality of life indicators and restrictive practices as well, not just incident counts, so you can see whether the person’s life is genuinely improving.