Google’s Advice on How to Hire an SEO – Search Engine Journal
Step Three: Technical Audit
After checking references and narrowing down your candidates, it’s time to request a technical audit. The SEO should come back with a prioritized list of what should be improved to make a site more search-friendly.
Those suggestions should be based on data collected during the audit, and be targeted toward providing a better experience for human visitors (not just search engines).
The SEO should be able to estimate the overall investment required by the business, and the positive impact that will be achieved as a result.
What to do After Hiring an SEO
Lastly, Google provides a few bits of advice on what to do after you’ve hired an SEO.