Which type of verification is best?
According to ISO, one is not "better" than another. The real question is – which one is appropriate? The user makes the decision based on perceived risks and relevant market drivers and conditions. This determines which of the four verification options, called conformity assessment, best suits their resources and needs.
ISO 14001:2004 outlines 4 options in Clause 1: Scope: "an organization that wishes to"
"c) demonstrate conformity with this International Standard by
1) making a self-determination and self-declaration, or
2) seeking confirmation of its conformance by parties having an interest in the organization, such as customers, or
3) seeking confirmation of its self-declaration by a party external to the organization, or
4) seeking certification/registration of its environmental management system by an external organization."
Options 3 and 4 are both third-party assessments options. Option 3 is based on the EnviroReady Report.
From these four, choose the option that best suits your needs.