Factory audits, like product inspections, need to be performed in an objective manner. A buyer that pays for audits of two factories should be able to compare the findings and use them to pick a supplier.
It means auditors should work with the same basic checklist for all their evaluations, and make a few adjustments in function of production processes or client requirements.
I proposed a basic checklist for audits to quality standards (based on the ISO9000 series) on the China Sourcing Blog. Here is the article: Factory Quality System: What Auditors Usually Check.
The idea is to help importers who visit their China suppliers but have no experience in operations/quality management. They can adopt the checklist I proposed as a general guideline to evaluate the reliability of each factory they visit… If they take the time for it!