This guide trains decision justification for the Advanced Diploma of Work Health and Safety: applying the reasonably practicable test from the model WHS framework, selecting controls by the hierarchy of control, building causal chains in investigations, and evidencing officer due diligence and WHSMS design. It includes two worked construction scenarios, a control decision table, a rubric-scored debrief exercise, and an adaptable preparation sequence with readiness checks.
Applying the five reasonably practicable matters to a live site decision
The model WHS Act weighs five matters: likelihood of the risk, degree of harm, knowledge the duty holder had or should have had, availability and suitability of controls, and whether cost is grossly disproportionate to the risk.
Work through the matters in order and tie each one to a stated fact. 'Likelihood' asks how probable harm is with current conditions, not in the worst imaginable case. 'Knowledge' includes what the duty holder should reasonably have known, so industry guidance and regulator alerts count even if unread. 'Availability and suitability' is factual: the control exists and can be sourced, so budget alone does not make it unavailable.
Note how this test differs from a risk matrix: the matrix ranks hazards for attention, while reasonably practicable decides whether a specific control must be adopted. Cost enters only as a disproportion question. The five matters also do not permit a 'zero risk' answer — the test accepts controls that reduce risk so far as reasonably practicable, which is exactly the reasoning your written answers must show.
- Worked scenario — excavation beside a live high-voltage conduit:
- Mistake: the planner writes 'hand dig only near services; vacuum excavation too expensive', treating cost as a veto and never comparing it against the risk.
- Better: weigh likelihood (live conduit confirmed in the dig zone), harm (electrocution), required knowledge (utility plans, location-service results), availability (hydro-vac crews bookable locally) — then record that cost is not grossly disproportionate to a fatality-level risk.
- Why it matters: the first version reads as a preference; the second as a decision a reviewer can follow from facts to control.
Selecting controls by hierarchy instead of by habit
The hierarchy ranks controls from elimination, substitution and isolation, through engineering controls, to administrative controls and PPE. Higher options remove the hazard; lower options depend on human compliance, so answers must justify defaulting down the order.
Practise classifying controls before judging them. A barricade that keeps pedestrians outside a slewing radius is isolation; a proximity alarm is engineering; a toolbox talk about plant awareness is administrative. The classification drives the argument: if a higher control is available, suitable and proportionate, choosing a lower one needs a reason grounded in the five matters — not a habit like 'workers prefer it'.
Residual risk is the other half of the concept. Every control leaves something behind, and advanced-level answers state what remains and how it will be watched: inspections, exposure measurements, consultation feedback or audit findings feed back into review. Pair each control in your scenarios with its monitoring mechanism. That pairing shows you understand a WHS decision as a managed, verifiable system rather than a one-off selection.
| Hazard | Habitual weak control | Hierarchy-aligned control | What the written answer adds |
|---|---|---|---|
| Mobile plant near workers on foot | Hi-vis vests and a toolbox talk | Segregated walkways and slew-zone barricades | Names isolation/engineering levels; states residual interface risk and how checks monitor it |
| Cutting concrete slabs | Disposable respirators | On-tool dust extraction, wet-cutting substitution | Justifies why respirators alone fall short; specifies exposure monitoring |
| Edge work at height | Harnesses and verbal reminders | Prefabricated guardrails installed before work starts | Explains fall elimination at source; notes inspection regime |
| Manual handling of facade panels | Lifting technique training | Panel jigs or vacuum lifters built into the task | Links substitution to task redesign; verification by task observation |
Investigations that reach causes instead of stopping at culprits
Strong investigations separate immediate causes, contributing conditions and organisational root causes. An answer ending at a worker's action leaves the system unchanged; trace each factor back to planning, design, resourcing and verification decisions.
Use layered questioning deliberately: for each factor you name, ask why it was true until you reach a decision someone could have made differently. Methods such as chained 'five whys' or factor-mapping frameworks keep the chain visible and guard against a single-cause story. Distinguish what happened (the energy path that injured the person) from why it was allowed (the controls that failed or never existed).
Recommendations then map onto causes: correcting the immediate condition may follow from an immediate cause, while root causes justify system changes — revised procedures, design changes, resourcing or supervision arrangements. Keep recommendations proportionate and assignable, each with a verification method, and check each one against the question 'would this have stopped the event?'. That discipline separates an investigation report from a blame memo and connects field events to management-system controls.
- Worked scenario — rigger struck by a falling shackle during a tandem lift:
- Mistake: the report stops at 'the rigger failed to secure the shackle' and recommends a refresher briefing — the chain ends one step above the injured worker.
- Better: trace why loose gear was tandem-lifted without a prepared container (planning gap), why the approved tether point was awkward to reach (fixture design), and why the lift plan review had no verification step (process gap); assign fixes at each level.
- Why it matters: blame-only findings leave the same energy path open on the next lift, and the causal chain reads as incomplete to any careful reviewer.
Designing a WHSMS that maps duties, not just documents
A WHS management system is an integrated plan-do-check-act structure assigning duties, consultation, risk processes, verification and improvement — not a folder of procedures. Advanced answers show how documents, roles and reviews connect across overlapping duty holders.
Anchor the system in the duty structure. A principal contractor, subcontractors and a client can each be a PCBU with overlapping duties over the same work, and the model WHS framework expects them to consult, cooperate and coordinate rather than assume someone else holds the risk. Contractor management, traffic management and high-risk work authorisations all sit inside this web — map who decides, who verifies and who reports.
Then connect documents to verification. A procedure no one audits is paper; an advanced answer pairs each commitment with evidence — inspection records, corrective action closure, consultation minutes, training currency. Consultation is a system component too: health and safety representative arrangements and committee processes generate information the system must act on. When revising a WHSMS, trace one workflow end to end and list where the system detects failure.
Evidencing officer due diligence, apart from the primary duty of care
Due diligence is the officer's duty to keep knowledge current, understand the business's hazards, ensure resources and processes, ensure information and response channels, and verify — distinct from the PCBU's primary duty of care and workers' duties.
Keep the duties distinct in every answer. The PCBU holds the primary duty to workers and others; officers discharge due diligence through governance behaviour; workers take reasonable care and follow reasonable instructions. Mixing them — for example, asking an officer to 'control the hazard' — signals confusion. Each duty has its own evidence base, so practise attributing the right obligation to the right role in every scenario you write.
Practise attaching workplace evidence to each due diligence element: a briefing log shows current knowledge; a site hazard register shows operational understanding; budgeted control programmes show resources; incident reporting rules show information flow; walkdown notes and audit actions show verification. Leading indicators — inspection completion, action closure times, training currency — demonstrate verification better than injury statistics, which report the past rather than governance activity.
A rubric-scored debrief exercise you can run weekly
Run a 25-minute loop: take one incident summary and one design decision, write a 250-word justification, then score it against the rubric below. Expected observations: correct duty attribution, weighed factors, named hierarchy levels, layered causal chains, stated monitoring.
The fixed frame makes writing fast under pressure: name the duty holders; list the facts; weigh the five reasonably practicable matters against those facts; select controls and name their hierarchy levels; state residual risk and its monitoring. Twenty-five minutes — fifteen writing, five scoring, five red-teaming by asking what a reviewer would challenge. Sources can be incident summaries from news reports or de-identified events from your own projects.
Score each rubric line 0, 1 or 2 and record the total. Treat a plateau at eight or more of ten as a learning milestone — evidence your reasoning structure is settling — not as a prediction of any assessment result. When a score stalls on one line, drill that line alone: five control classifications, or five causal chains, before returning to full justifications the following week.
- Duty attribution (0-2): correct obligation sits with PCBU, officer or worker; no role mixing.
- Factor coverage (0-2): four of five reasonably practicable matters, each tied to a stated fact.
- Control placement (0-2): each control labelled with its hierarchy level; reasons given for lower-level choices.
- Causal depth (0-2): incident chains reach three or more layers beyond the front-line act.
- Monitoring (0-2): residual risk named, with the inspection, measurement or consultation method that watches it.
An eight-week sequence and concrete readiness checks
Spend the first fortnight building a framework glossary with your own site examples, then alternate weekly scenario debriefs with timed writing. Reserve the final fortnight for closed-book rewrites of earlier scenarios until the readiness checks pass.
A realistic sequence: weeks one and two, define the core concepts — PCBU, officer, worker, reasonably practicable, hierarchy, consultation — each with one construction example you wrote yourself. Weeks three to six, run the debrief loop twice weekly and write one 250-word timed justification; rotate themes across WHSMS design, investigation, control selection and due diligence evidence so no topic cools. Adjust the split to your calendar — the rotation matters more than the exact weeks.
The final fortnight, rewrite your earliest scenarios without notes and compare against your rubric scores from weeks three to six; improvement shows the structure has stuck. Add unfamiliar scenarios to test transfer beyond your own sites. One administrative note: current packaging, versions and entry details for BSB60619 sit with training.gov.au, so confirm delivery specifics with your registered training organisation rather than any study guide.
- Write a 150-word reasonably practicable justification for an unfamiliar hazard from a blank page, hitting four of the five matters.
- Classify any control into its hierarchy level on sight and state the residual risk it leaves.
- Name the due diligence elements with one workplace evidence example each.
- Rebuild both worked scenarios' causal chains from memory, reaching system-level causes.
- Fresh-scenario rubric scores plateau at your target without notes.
References and further reading
Use these references to explore the concepts and check the latest information from the relevant organizations.