There are several aspects to your question.
Our performance auditors have various skills. For instance, we have engineers and lawyers. These people have mastered a given field, but they are not professional chartered accountants. There are professional chartered accountants who do performance audits, but there are also auditors who possess other skills that allow them to examine different areas.
To complete an audit, it is also important to obtain the help of other people, for instance actuaries or other professionals. Our office does not have expertise in those areas, and it is important that we hire those people. They must also be independent and objective, and we have an assessment process that allows us to ensure that.