include a second-party audit process in their supplier management approach."
With all due respect, allow me to respond in defense of @Jim Wynne 's previous comment to this . You are correct in regards to the possible benefits of auditing members of the supply chain if /when needed. Indeed , when developing an IATF 16949 management system I consistently council organizations to establish criteria for what MAY be the impetus for a 2nd party audit, and of course the competency criteria for any who may be involved in performing those audits (7.2.4).
I would, however, council that many coming to this site for answers are very new to this and other topics. Therefore, it is our collective responsibility to ensure our opinions are left at the door unless of course we are stating that comments made are indeed simply our opinions. As with other standards, if there is not a specific requirement, then the requirement does not exist. Therefore, @Jim Wynne 's comment is indeed correct that there is no requirement to perform supplier audits. This of course does not negate your opinion that it can be one option for for assisting with supplier development and/or supplier monitoring.
On a slightly different topic, we should also take care in the use of subjective terms such as "critical". In my experience, a quick survey of what a term means within an organization often results in a multitude of differing answers. Therefore, I council organizations if/when they wish to use terms such as "key" or "important" or "critical" etc..etc..., to have a specific established definition of any such term in order to prevent confusion.
Hope this helps.
Be well.