What IAF MD5 requires when you calculate audit days

IAF MD5 is the mandatory document that sets how a certification body determines audit duration for management system audits. Most people know it as the table: effective number of personnel on one axis, audit days on the other. The table is where the calculation starts. What an accreditation assessor actually reviews is everything you did after looking it up.

Effective personnel is not headcount

The starting figure is the effective number of personnel, and it is a calculated number, not the one on the payroll. Part-time staff convert to their equivalent. Seasonal and temporary personnel count when they are part of the certified activity. Repetitive work performed across several shifts can be reduced, but only when the shifts genuinely do the same thing under the same controls — and that reduction has to be justified, not assumed.

Get this number wrong and everything downstream is wrong: the quote, the plan, the invoice and the defensibility of the audit. It is also the number clients push hardest on, which is exactly why the reasoning behind it has to live in the file rather than in the head of whoever prepared the proposal.

The adjustment factors, and the limit on them

From that baseline you adjust in both directions. Upward for complexity: several processes, high-risk activity, regulated product, multiple standards audited separately, languages that force interpretation. Downward for maturity: an integrated system already certified against another standard, a previously audited site, a process that is highly automated or highly repetitive.

Two limits matter more than the rest. Reductions are bounded — the document caps how far below the table you may go, and stacking justifications to get under that cap is precisely what assessors look for. And at least eighty per cent of the calculated duration has to be spent auditing on site, at the sites where the activity happens. Travel, report writing and the closing meeting are not audit time.

The record is the deliverable. Not the number — the number plus which factors you applied, in which direction, by how much, and why. Bodies that keep that reasoning in a spreadsheet formula end up reconstructing it years later in front of an assessor. Bodies that write it down at quoting time have already answered the question. The Application & Quote Agent does the calculation and writes the justification with it, so the reasoning ships with the proposal instead of being rebuilt from memory.