Welcome to the Q&A Forum

Hi, Late last year the company I work for launched two new websites that, at the time, we believed were completely separate from our main website. The two new websites were set up externally and were not well-planned from an SEO perspective (LOTS of duplicate content) - hence, they have struggled to rank on Google. Since the launch of the new websites we have also noticed that our main website (that previously ranked very well) has suffered a decline in visitation and search engine rank. We initially attributed this to a number of factors, including the state of the market, and ramped up our SEO efforts (seeing minor improvement). We have since realised that these two new websites have been set up as subdomains of our main website, with MOZ displaying the same domain authority and root domain backlink profile. My question is, do poor quality subdomains affect the ranking performance of a root domain? I have not yet managed to find a definitive answer. Please let me know if more information is required - I am quite new to the whole SEO concept. Thanks! Amy