Once you have asked an SEO Manager candidate for a second round interview, I would make them take a test to better understand what their experience and knowledge base truly is without preparation. Not only is this an expertise test but is an aptitude test based on how they answer considering there can be multiple answers. This test covers the core areas that an SEO must know, yet are a mix of top level and detail based questions.
Education (any good seo subscribes to many sites and has dozens of tools they use)
Name 3 websites you read SEO news from?
Name 3 SEO Tools & 3 Link Building Tools
Strategy (An SEO needs to have high level thinking and be able to describe strategies verbally as well as written)
How would you optimize differ for Bing than you would for Google
What would be 3 things done differently in a local search campaign
Technical (The foundation of an SEO pyramid and separates the children from the adults in the SEO world)
Show me 3 different types of canonical redirects
Name 3 ways to reduce page load time?
On-Page (anything related to on-page content and tags)
How can a PDF be optimized?
What’s the value of a meta-description?
Off-Page (The other half of the battle – social media, link building etc)
Would you ever want links with anchor text ‘click here’? (why or why not?)
Name 4 types of links
Analytics (All your work means nothing if you can’t quantitatively prove your efforts)
How do you account for Not-provided visits from Google?
Name 2 ways to install Google Analytics to a web page
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