Marketing Strategy Blog

The Most Important SEO Ranking Factors of 2015

Search Ranking Factors

Every two-years, athletes around the world compete for Olympic medals, and a global audience eagerly watches. SEO has its own Olympics—the Olympics of organic search engine ranking factors. And the greater digital marketing community eagerly consumes the data.

Every year, the inbound marketing software company Moz runs extensive studies to determine the features of websites that are associated with higher search engine rankings. This year Moz improved their study by partnering with the data-based services SimilarWeb, DomainTools and Ahrefs for deeper data insights. For the 2015 study, Moz’s data scientist Dr. Matt Peters examined the top 50 Google results of 16,521 search queries, resulting in over 700,000 unique URLs. In total, the 2015 Search Ranking Factors study measured over 170 organic search ranking correlations.

And the winners are:

Gold Medal: Domain-level and Page-level Links

The ever-victorious link wins the gold, yet again. As has been the case for many years, it is not just the number of links to your site, but the quality of links that matter. Elements associated to domain-level and page-level links with the strongest influence on search engine ranking include:

  • Raw quantity of unique links from high-authority sites
  • Topical relevance of linking domains and pages
  • Popularity and trust of the domain measured by Moz
  • Diversity of linking domains and anchor text link

Silver Medal: Page-level Keyword & Content-Based Features

Keyword- and content-based features highlight Google Hummingbird’s impact on search rankings. Google Hummingbird was released in August 2013, and allows Google to better understand the meaning behind words—what Google coined as “conversation search.” Check out The ROI of SEO for more information about Google Hummingbird. The top page-level keyword & content-based ranking factors are:

  • On-page optimization of keyword usage
  • Topic modeling within content
  • Content quantity, quality and relevance
  • Keyword usage, such as in body text

Bronze: Page-level Keyword-agnostic Features (Tie)

These page-level features account for non-keyword ranking factors, such as page length, page load speed and international targeting. A few of the negative factors include lengthy server response time and lengthy URLs. The top page-level keyword-agnostic elements affecting rankings are:

  • Total number of links
  • Page has hreflang declaration, such as hreflang for language and regional URLs
  • Number of internal and external links
  • The use Google Analytics

Bronze: Engagement & Traffic/Query Data (Tie)

These ranking factors are focused on engagement with the SERP (search engine ranking position) listing; visitor traffic through the listing; usage signals when on the resulting website; and the quantity, quality and CTR of queries (both on the domain and page level). Factors affecting ranking position are:

  • Third-party metrics from social media sources like Facebook, Twitter and Google+
  • Brand and domain mentions across the web
  • Total search and direct site visits
  • Total time on-site and number of page views


Not quite making it onto the winner’s podium but important nonetheless to a comparatively lesser degree, runner-up elements impacting organic search rankings include:

  • Domain-level Brand Metrics: Mentions of brand or domain offsite in the news, media and press
  • Domain-level Keyword Usage: Exact match and partial match uses in the domain
  • Domain-level Keyword–agnostic Features: Such as domain name length and SSL certificate
  • Page-level Social Metrics: Quality and quantity of page level tweeted links, Facebook Shares, etc.

While not specifically mentioned in the report, 88% of search marketers surveyed by Moz believe that mobile friendliness will be the number one ranking factor to increase in importance over the coming 12 months. Proactive marketers will want to correct any existing mobile issues with their sites immediately to tee their sites up for SEO success moving forward.


With winners there must be losers, and in the case of the SEO Olympics we are referring to factors negatively impacting visibility. A few features to which Moz assigned a high spam score, and therefore are to be avoided, are:

  • High proportion of ads, navigation and links in a page
  • High number of links relative to content on a site overall
  • Extensive amount of external links in sidebars and footers
  • Crawlers receive a valid response from only a small number of pages

Putting Your Customers First

Moz’s annual search ranking factors study is always exciting, but one thing that has not changed is Google’s intention to put searchers first when ranking organic search results. Keep that in mind when designing your website, creating content, and partnering with media, bloggers, and the press. Put your user first; provide the user with a responsive site accommodating different screen dimensions; include quality, relevant, and informative content on your site; and engage influencers, partners, bloggers and the media to share information. By consistently doing the right thing for your customers, you will inherently be adhering to SEO best practices and may even win your own Olympic medal in SEO.