What is the difference between a functional capacity assessment and a diagnostic assessment for the NDIS?

A diagnostic assessment determines whether a person meets criteria for a specific condition (e.g., ASD, intellectual disability, PTSD). A functional capacity assessment describes how a confirmed disability affects the person's ability to perform everyday activities across life domains. The NDIS requires both — a diagnosis establishes eligibility, while functional capacity determines the level and type of funded supports. Many psychologists write comprehensive reports that include both diagnostic and functional components, but the functional section must be the most detailed and specific part of the report.

What framework should I use for describing functional capacity?

The NDIS is broadly aligned with the World Health Organization's International Classification of Functioning, Disability and Health (ICF) framework, which describes functioning across body functions, activities, and participation. In practice, the NDIA assesses functional capacity across eight domains: mobility, communication, social interaction, learning, self-care, self-management, daily living, and work. You do not need to use ICF codes in your report, but structuring your functional descriptions around these domains ensures your report addresses the areas the NDIA assesses.

Should I use standardised functional assessment tools?

Yes. Standardised tools add credibility and objectivity to your functional descriptions. The WHODAS 2.0 (World Health Organization Disability Assessment Schedule) is well-regarded by the NDIA because it directly measures disability-related functioning. The ABAS-3 (Adaptive Behavior Assessment System) and Vineland-3 are standard for intellectual and developmental disability assessments. The SIS (Supports Intensity Scale) is useful for describing the type and intensity of supports needed. Always supplement standardised measures with clinical observation and informant reports for a complete picture.

How do NDIS support categories relate to functional capacity?

NDIS support categories map to the areas of functioning your assessment describes. Core Supports (assistance with daily life, transport, consumables, social and community participation) address ongoing daily functional needs. Capacity Building supports (including psychology under 'Improved Daily Living') fund interventions that build the participant's capacity over time. Capital supports fund assistive technology and home modifications. When you describe a functional limitation, your corresponding recommendation should reference the relevant support category so the planner can allocate funding to the correct budget line.

Can I recommend behaviour support in my functional capacity assessment?

Yes, and if the participant displays behaviours of concern (sometimes called 'challenging behaviours'), you should. Under the NDIS, behaviour support is a Capacity Building support category. If you are recommending a behaviour support plan, note that the NDIS Quality and Safeguards Commission requires behaviour support plans that include restrictive practices to be developed by an NDIS-registered behaviour support practitioner. Your functional capacity assessment can identify the need for behaviour support and describe the behaviours, but the formal behaviour support plan is a separate document.

NDIS Functional Capacity Assessment: Psychology Report

International|12 min read|Updated 2026-03-20|Clinically reviewed

What Is an NDIS Functional Capacity Assessment?

An NDIS functional capacity assessment is a clinical evaluation that describes how a person's disability affects their ability to perform everyday activities and participate in community life. While a diagnostic assessment answers the question "What condition does this person have?", a functional capacity assessment answers the question "What can this person do, what can they not do, and what supports do they need to close the gap?"

The NDIS is built on a functional model of disability, not a medical model. This distinction is fundamental to understanding what the NDIA needs from your report. Two people with the same diagnosis — say, Autism Spectrum Disorder Level 1 — may have vastly different functional capacities and therefore vastly different NDIS plans. The differentiator is not the diagnosis but the functional impact. Your functional capacity assessment is the primary evidence that determines the level of funded supports a participant receives.

As a psychologist, you are uniquely positioned to assess functional capacity in cognitive, emotional, social, and behavioural domains. Your assessment should go beyond what standardised tools measure to include clinical observation, informant reports, and contextual factors that affect the person's real-world functioning.

When You Need It

You will conduct and document a functional capacity assessment in these situations:

Initial NDIS access requests — as part of a comprehensive assessment establishing both diagnosis and functional impact for a new NDIS applicant
Plan reviews requiring updated functional evidence — when the participant's functional capacity has changed and updated evidence is needed for their next plan
Supported Independent Living (SIL) applications — where detailed functional evidence is required to justify high-intensity support packages
AAT appeals — where the participant is challenging a plan decision and requires comprehensive functional evidence
Behaviour support referrals — where a functional assessment of behaviour and its antecedents is needed to inform a behaviour support plan
Transition planning — when a participant is transitioning between life stages (e.g., school to post-school, family home to supported accommodation) and functional capacity in the new context needs assessment

Key Components / Requirements

Functional Domains

The NDIA assesses functional capacity across eight domains. Your report should address each domain that is relevant to the participant's disability:

1. Mobility: Can the participant move around their home and community independently? Can they use public transport? Do they require mobility aids or physical assistance?

2. Communication: Can the participant express their needs and understand others? Do they require augmentative and alternative communication (AAC) supports? Are there pragmatic language difficulties that affect social communication?

3. Social Interaction: Can the participant form and maintain relationships? Can they navigate social situations appropriately? Do they understand social norms and expectations?

4. Learning: Can the participant acquire new skills? How do they process information? What supports do they need to learn and apply new knowledge in daily life?

5. Self-Care: Can the participant manage personal hygiene, dressing, eating, and health management independently? What level of prompting or physical assistance is required?

6. Self-Management: Can the participant manage their emotions, make decisions, solve problems, and manage their own safety? This domain is particularly relevant for psychologists.

7. Daily Living: Can the participant manage household tasks, meal preparation, shopping, and household maintenance? Can they manage finances and administrative tasks?

8. Work: Can the participant engage in employment, volunteering, or meaningful occupation? What supports would they need to access and maintain employment?

Descriptive Standards

For each domain, describe functioning at three levels:

What the person can do independently — their strengths and existing capabilities
What the person can do with support — and what type and level of support is needed
What the person cannot do — even with support, at this time

Use concrete, observable language. Quantify wherever possible — frequency of behaviours, duration of activities, number of prompts required. Avoid subjective descriptors like "significant difficulties" without specifying what those difficulties look like in practice.

Contextual Factors

Describe the environmental and personal factors that affect functioning. A participant may function differently in familiar versus unfamiliar environments, with versus without sensory accommodations, or during different times of day. These contextual factors are important for the NDIA to understand when planning supports.

Support Mapping

For each identified functional limitation, map the corresponding NDIS support category and recommend specific supports. This is where your functional assessment translates into actionable funding recommendations.

NDIS Functional Capacity Assessment — Intellectual Disability with Behaviours of Concern

Functional Capacity Assessment — NDIS

Participant: Liam Patterson (he/him) Date of Birth: 09/12/2003 NDIS Number: 4XXXXXXXX Date of Assessment: 18/02/2026 and 25/02/2026 Assessor: Rebecca Tran, Registered Psychologist, AHPRA PSY0002345678

Background: Liam is a 22-year-old man with a confirmed diagnosis of Intellectual Disability (Moderate, IQ 48, assessed 2018) and Attention Deficit Hyperactivity Disorder (Combined Presentation). He lives at home with his parents, Mr David Patterson and Ms Karen Patterson. He attends a day program three days per week. This functional capacity assessment has been requested by Liam's support coordinator to inform his upcoming plan review, with a particular focus on the level of support worker assistance required and the need for behaviour support services.

Assessment Methods:

Two clinical observation sessions (day program and home environment)
Structured interview with Liam (adapted for intellectual disability)
Informant interviews with both parents and day program coordinator
Vineland Adaptive Behavior Scales, Third Edition (Vineland-3) — parent/caregiver form
Supports Intensity Scale (SIS) — completed with informant input
Functional Behaviour Assessment (direct observation and ABC data review)
Review of current NDIS plan and support coordinator progress notes

Functional Capacity by Domain:

Self-Care (Vineland-3 Daily Living Skills: Standard Score 42, Very Low): Liam can feed himself independently with finger foods and a spoon. He requires verbal prompting to use cutlery correctly and physical assistance to cut food. He can shower with a visual schedule posted in the bathroom but requires a verbal prompt to initiate the routine and checks to ensure he has washed all body parts (he consistently misses washing his hair unless prompted). He requires full assistance to select weather-appropriate clothing and cannot tie shoelaces. He can brush his teeth with a visual prompt card but does not initiate this without prompting. He cannot manage medication independently — his parents dispense all medications.

Communication (Vineland-3 Communication: Standard Score 51, Very Low): Liam communicates using short sentences (3 to 5 words) and approximately 300 functional vocabulary words. He can make basic requests ("I want juice," "Go to park") and answer simple yes/no questions. He cannot describe internal states (emotions, pain levels) with specificity — he uses "bad" for all negative states. He does not understand sarcasm, idiom, or indirect requests. He can use a visual choice board to make selections from 4 to 6 options. He cannot use a telephone independently and cannot read beyond single high-frequency words (his name, "stop," "exit").

Social Interaction (Vineland-3 Socialization: Standard Score 46, Very Low): Liam seeks social contact and enjoys being around peers at his day program. He approaches others for interaction but does so by touching their arm or standing very close, which peers and staff find intrusive. He does not understand personal space boundaries despite repeated social skills instruction. He can participate in parallel activities alongside peers but cannot engage in cooperative activities without 1:1 support worker facilitation. He becomes distressed (crying, hitting himself on the thigh) when peers reject his social approaches. He does not have any independent friendships outside his family and day program.

Self-Management: Liam has limited emotional regulation capacity. When frustrated or overwhelmed, he displays behaviours of concern including self-injurious behaviour (hitting his thighs and head with open palm, approximately 8 to 12 episodes per week as reported by parents), property damage (throwing objects, approximately 2 to 3 episodes per week), and elopement (leaving the day program building without warning, approximately once per fortnight). These behaviours have increased in frequency and intensity over the past six months, coinciding with the departure of a preferred support worker. Liam cannot identify his emotional state or use self-regulation strategies without real-time prompting from a known support person. He requires 1:1 supervision at all times when in community settings due to elopement risk and inability to assess environmental safety (e.g., traffic, stranger danger).

Daily Living: Liam can complete single-step household tasks with a visual schedule (e.g., putting plates in the sink, putting clothes in the washing machine). He cannot sequence multi-step tasks (e.g., doing the laundry from start to finish) without step-by-step prompting. He cannot prepare any meals independently — he can assist with supervised tasks such as stirring and pouring but cannot safely use a stove, oven, or sharp implements. He has no concept of money management and cannot make purchases independently.

Mobility: Liam is physically mobile and does not require mobility aids. However, he cannot navigate the community independently due to his intellectual disability — he does not understand traffic signals, cannot read street signs, and becomes disoriented outside a 200-metre radius of familiar locations. He cannot use public transport independently.

Learning: Liam can learn new skills through repeated modelling, visual supports, and high-frequency practice in natural environments. He requires an average of 30 to 50 repetitions to acquire a new routine step, compared to 3 to 5 repetitions for a neurotypical peer. Skills do not generalise across contexts without explicit teaching in each new context. He has made progress in his day program on vocational tasks (sorting, packaging) but requires ongoing 1:1 instruction and cannot yet perform these tasks without supervision.

Behaviours of Concern — Summary: A functional behaviour assessment indicates that Liam's self-injurious behaviour primarily serves an escape function (from demands perceived as too difficult) and a communication function (expressing frustration when he cannot articulate his needs). Property damage is maintained by the same functions. Elopement appears to serve a sensory-seeking function — Liam seeks movement and outdoor sensory input when overstimulated in indoor environments. A formal behaviour support plan is recommended.

Support Recommendations:

Behaviour Support Practitioner (Capacity Building — Improved Relationships): 30 hours per year for development and oversight of a comprehensive behaviour support plan addressing self-injury, property damage, and elopement. A registered NDIS behaviour support practitioner is required.
Psychology (Capacity Building — Improved Daily Living): 20 hours per year for adapted social skills training and emotional regulation skill building, delivered in natural environments with support worker involvement for generalisation.
Support Worker — Community Access and Daily Activities (Core Supports): Increase to 40 hours per week of 1:1 support, reflecting the level of supervision Liam requires across self-care, community access, and daily living due to safety risks associated with behaviours of concern and limited independent functioning.
Day Program (Core — Social and Community Participation): Continue 3 days per week with 1:1 support worker allocation during program hours.

Rebecca Tran Registered Psychologist | AHPRA PSY0002345678

This is a sample for educational purposes only — not real patient data.

How to Write It

Step 1: Assess in natural environments. Functional capacity is context-dependent. Wherever possible, observe the participant in their home, day program, workplace, or community settings — not just in your office. A person who appears to function well in a structured clinical setting may have significant difficulties in unstructured, real-world environments.

Step 2: Use multiple informants. Interview the participant (adapting your approach for their communication level), family members, support workers, day program staff, and other treating professionals. No single informant has the complete picture.

Step 3: Quantify everything. Instead of "requires assistance with self-care," write "requires an average of 4 verbal prompts and 2 physical assists to complete a 7-step morning hygiene routine." Numbers give the NDIA planner concrete information for support allocation.

Step 4: Describe the support gradient. For each activity, describe what level of support enables the person to participate — is it verbal prompting, visual supports, physical assistance, full hand-over-hand guidance, or complete support worker completion of the task? The support gradient helps the planner determine the intensity of funded supports.

Step 5: Link every limitation to a support recommendation. Each functional limitation you identify should have a corresponding recommendation in the support section. If you describe a limitation without recommending a support to address it, the planner has no basis to allocate funding.

Step 6: Acknowledge strengths. The NDIS is capacity-building in philosophy. Document what the person can do, what they are motivated to learn, and where growth is possible. This is not about minimising disability — it is about demonstrating that funded supports will enable progress, not just maintenance.

Common Mistakes

Writing a diagnostic report with a thin functional section. If your report has three pages of diagnostic detail and half a page of functional description, it is the wrong way around for NDIS purposes. The functional section should be the longest and most detailed part of the report.
Using clinical language instead of functional language. "Executive dysfunction" means nothing to a planner. "Cannot sequence a three-step morning routine without step-by-step prompting" is functional language that directly informs support allocation.
Describing capacity in your office, not in real life. A participant who can have a conversation with you in a quiet clinical room may be unable to communicate in a noisy community setting. Assess and describe real-world functioning.
Failing to address behaviours of concern. If the participant displays behaviours of concern, you must describe them in functional terms (topography, frequency, intensity, duration, and function). Omitting this information means the participant will not receive behaviour support funding.
Not using the NDIS support categories in recommendations. If you recommend "therapy," the planner has to guess which support category to allocate it to. Name the category explicitly — "Capacity Building — Improved Daily Living" for psychology, "Core Supports — Assistance with Daily Life" for support workers.
Confusing functional capacity with functional performance. Capacity is what the person can do under optimal conditions. Performance is what they actually do in daily life. Both matter — but the NDIA funds supports based on what the person needs to do in their actual daily life, not what they could theoretically do under ideal circumstances.

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