When a peer reviewer asks why the sample size is 62, 'the इंजन picked them' is not an उत्तर. CORAA renders the SA 530 formula explicitly, sample size equals ceiling of (confidence factor × population value) divided by performance मटीरियलिटी. Confidence factors derive from the Poisson distribution. Selections are seeded, peer reviewers running the same seed obtain identical वाउचर.
Two paths to the same audit conclusion. One leaves traces; the other doesn't.
For each Working Paper, the ऑडिटर sets the जोखिम of Material Misstatement, High (95% confidence), Medium (90%), or Low (80%). The confidence factor follows: 3.0 / 2.3 / 1.6 from the Poisson distribution at -ln(α).
Sample size = ceil((confidence factor × population value) / Performance मटीरियलिटी). Worked example: Trade Payables population ₹5 crore, PM ₹35.8 lakh, high जोखिम = ceil((3.0 × 5,00,00,000) / 35,80,000) = 42 वाउचर. The formula is rendered on the Working Paper.
Locking generates the deterministic वाउचर selection per SA 230 Para. 8. The seed is derived from एंगेजमेंट ID + balance head code. A peer reviewer running the same seed obtains the same वाउचर. Locked plans are पढ़ें-only; unlock requires a documented note.
Every Working Paper renders the sample-size formula explicitly: ceil((Confidence factor × Population value) / Performance मटीरियलिटी). The confidence factor, the population value, and the PM सभी show on the पृष्ठ. The ऑडिटर can defend the sample size on the spot.
ICAI SA 530 Para A11 + Appendix 3 derives confidence factors from -ln(α) where α is the acceptable सैम्पलिंग जोखिम. High जोखिम → 95% confidence → CF 3.0. Medium → 90% → CF 2.3. Low → 80% → CF 1.6. CORAA renders the math.
Some rows demand 100% testing regardless of sample math, वर्ष-end manual journals (last 14 दिन), related-party transactions, employee benefits over PM threshold. Configure once per एंगेजमेंट; CORAA enforces.
Selection is seeded from a deterministic value: एंगेजमेंट ID + balance head code, hashed via SHA-256. A peer reviewer running the same seed obtains the same वाउचर. SHA-256 algorithm and numpy version are pinned, so identical seeds yield identical selections वर्ष later.