should be carried out well in advance of the on-site audit.
Based on these results, the audit team agrees on a manageable
number of scenarios (generally, two or more) and a representative
sample of barriers (usually with a maximum of 20–30)
to be used as focal points during the audit. The choice of scenarios
and the sample of barriers are both determined by the
purpose of the audit and through guidelines provided with
the audit and described below.