A-100 Planning — strategy, materiality, risk
A-100 is the first workpaper. It sets the boundaries for everything else — what's material, where the risk lives, who does what, and what the strategy is. Per ISA 300 + 315 + 320, this must be documented before fieldwork begins.
What goes in A-100
Eight planning sub-procedures, each tagged to its ISA:
Understand the entity (ISA 315)
Industry, regulatory environment, ownership, key contracts, IT environment, internal-control weaknesses. Capture in the workpaper's free-text section + attach the client's organisation chart.
Compute materiality (ISA 320)
The system auto-computes 4 bases: 1% of revenue, 0.5% of total assets, 5% of profit before tax, 1% of equity. Pick the lowest as overall materiality. Performance materiality = 75% of overall.
Identify risk areas (ISA 315 + 240)
For each FS area: assess inherent risk (low/medium/high), control risk, fraud risk indicators, and prior-year findings. Drives sample-size and procedure depth in fieldwork.
Set the audit strategy (ISA 300)
Substantive vs reliance approach, audit timing (interim + final), team composition, specialist involvement (tax, IT, valuation).
Engagement-team allocation
Partner, EQCR (if applicable), manager, senior, staff. Capability-matrix lookup ensures each member has the right skills for their assigned area.
Independence + ethics confirmation (ISA 220)
Each team member confirms independence in writing. Captured as a tick + signature in the workpaper.
Communication with TCWG (ISA 260)
Plan how + when you'll communicate with Those Charged With Governance — usually a planning meeting + written agenda.
Sign-off as preparer
Manager (or senior) signs A-100 as preparer, partner reviews + signs as reviewer. Status moves draft → preparer_done → reviewer_done.
Materiality calculator
Form fields you'll fill
Inherited from job's fiscal year. Locks the date window for all sampling.
Drives capacity planning + appears on the deadline dashboard.
Override allowed but requires written justification — captured in audit log.
Lower if higher risk. Drives sample-size formulas downstream.
Inherent · Control · Fraud · Prior-year findings. 1 row per area minimum.
The "why" behind your approach. Becomes the planning narrative in the audit pack.
On any audit job, click Workpapers → A-100 and you'll see materiality auto-computed from the prior-year FS (or current-year if mid-fieldwork). Override the basis and watch the audit log capture the change with your reason.
Don't pick the highest materiality "to make life easier" — if a regulator reviews the file and your materiality is unjustifiably high, the entire opinion is at risk. Always pick the lowest of the four bases unless you have a documented reason (e.g. PBT distorted by a one-off).
If a risk row is rated high, the system flags the related workpaper and forces deeper sample sizes during fieldwork. Use this to your advantage — be honest in the risk assessment, and the system protects you.
What's next
A-100 signed. Materiality set. Risk register populated. Now the auditor needs the client's Trial Balance — the foundation of every subsequent number. Phase 2 covers the import.