Task demands analysis vs job demands analysis — what is the difference?
The distinction is one of scope. A job demands analysis (JDA) — also called an inherent requirements of the job (IROJ) document — covers the full demand profile of a role across all five demand categories (physical, cognitive, environmental, organisational, interpersonal). It is the clinical instrument used for pre-employment screening and return-to-work capacity targets.
A task demands analysis examines a single discrete task in detail — how it is performed, what loads are involved, what postures are adopted, how frequently the task occurs, and what control measures apply. Where the JDA asks “what are all the demands of this role?”, the task demands analysis asks “what are the demands of this specific activity?”
| Job Demands Analysis (JDA / IROJ) | Task Demands Analysis (TDA) | |
|---|---|---|
| Scope | Full role — all tasks and demands | Single task or activity |
| Primary use | PES, RTW capacity targets, health surveillance | Manual handling risk, SWMS, modified duties |
| Output | Clinical instrument — signed, version-controlled | Risk assessment record — part of SWMS or WHS management system |
| Who conducts it | OHS clinician (OT, EP, OH physician) | OHS officer, OT, or trained safety practitioner |
| Trigger | New role, PES program, RTW case | New task, equipment change, injury pattern, SWMS review |
When task demands analysis is used
Manual handling risk assessment
The WHS Regulations require employers to identify, assess, and control hazardous manual tasks. A task demands analysis is the structured method for doing so. It documents the specific loads, forces, postures, and frequencies involved in a task, identifies the risk factors that make the task hazardous (e.g. load weight exceeding recommended limits, awkward posture, high repetition), and documents the control measures in place or required.
Safe Work Australia's Hazardous Manual Tasks Code of Practice (2022) describes the task assessment process in detail. The task demands analysis is the record that demonstrates compliance with that process.
Safe Work Method Statements (SWMS)
Under the WHS Regulations, SWMS are required for high-risk construction work. A task demands analysis underpins the hazard identification and risk assessment sections of the SWMS by documenting what the task physically requires — what loads are handled, what postures are adopted, what exposures are present — and what control hierarchy applies.
A SWMS without a task demands analysis is a procedural document without a risk assessment foundation. Regulators auditing SWMS quality look for evidence that the hazard identification was grounded in actual task observation — not templated from a generic SWMS library.
Return-to-work modified duties planning
When designing modified duties for a worker returning from injury, the RTW coordinator needs to know not just the demands of the full role, but the demands of each specific task that makes up the role. A task demands analysis for each component task allows the coordinator to construct a graduated RTW plan that progressively reintroduces tasks as the worker's functional capacity recovers.
This is the complement to the role-level JDA — the JDA defines the ultimate target; the task demands analysis defines the intermediate steps.
What a task demands analysis documents
A complete task demands analysis covers the following elements for each discrete task:
Task description
A clear description of what the task involves — the specific activity, the equipment or materials used, and the work environment in which it is performed.
Physical demands
Loads handled (weight, size, shape), forces exerted (push/pull in Newtons or kg equivalent), postures adopted (trunk rotation, reaching, kneeling, overhead), and vibration exposure (HAV/WBV).
Frequency and duration
How often the task is performed per shift (occasional, frequent, constant), and how long each instance lasts. A task that is performed constantly at moderate load may be higher risk than an infrequent high-load task.
Hazard factors
The specific risk factors that make the task hazardous — load weight exceeding action limits, repetitive motion above threshold, sustained awkward posture, contact stress, and environmental aggravators (heat, vibration, fatigue).
Control measures
The hierarchy of controls applied to reduce risk: elimination (remove the task), substitution (change the method), engineering controls (mechanical aids, modified equipment), administrative controls (job rotation, load limits), and PPE where applicable.
Residual risk rating
The risk level after controls are applied — the basis for SWMS sign-off and for determining whether the modified task is appropriate for a worker with specific functional limitations.
How the TDA connects to the JDA
The task demands analysis and the job demands analysis are complementary — not competing — instruments. The JDA is the aggregate of all the task demands for a role, presented as a clinical instrument for fitness-for-work decision-making. The TDA is the detailed record of individual task risk, used for hazard management and modified duties planning.
In OccuSpan, task-level demand data from the IROJ module feeds into the physical demand profile of the role. When a worker is on a graduated RTW plan, the coordinator can view individual task demands against the worker's current functional capacity — rather than comparing only against the aggregate role profile.
Recommended reading: For the full IROJ/JDA framework — including legal obligations, five demand domains, and how the document is used across PES, RTW, and health surveillance — see the Job Demands Analysis guide and the Inherent Requirements of the Job guide.
OccuSpan IROJ Module
Role-level and task-level demands in one system
OccuSpan's IROJ module captures demand data at both the role level and the task level. Pre-employment screens, RTW plans, and modified duties packages all reference the same underlying demand data — no manual reconciliation required.
See PES module