"Pages with schema.org integrations rank better by an average of four positions compared to pages without schema.org integrations"
This being probably the most notable finding from the final version of the +Searchmetrics
"study of tens of thousands of keywords and more than half a million domains" headed "Schema.org in Google search results" (see the request button at the bottom of the page for the full PDF):http://www.searchmetrics.com/en/knowledge-base/schema/
The study authors are quick to note that correlation does not necessarily imply causation, although they correctly acknowledge that there's a logical connection between structured data use and search engine visibility."Whether the use of HTML markups does genuinely affect the ranking of a domain, as it would appear from the data, is hard to say. In fact, it may be due in part to interaction with other factors.""However, it can be said that the inclusion of HTML tags from schema.org to clearly flag up the content of the page will greatly help search engines better understand the Web’s content – and that is an essential consideration for a good ranking."
Other notable factoids from the study:
- Only 0.3% of domains in their sample included schema.org
- "Google enhances search results with schema.org
markups in more than 36% of keyword queries" 
- Movie, Offer, TVSeries and Review were the item types that most often ended up generating rich snippets in the SERPs (compare this to the most common schema.org
classes by domain from the lastest Common Crawl data - WebPage, Article, Blog, Product - and most common schema.org
classes by no. of entities - Product, Offer, Person, PostalAddress, Organization)
 Making for the best pie chart evah
 I'm interpreting this as "for 36% of our sample queries we observed a rich snippet in the top 50 results [their query depth] that appeared to be based on the presence of schema.org
markup." The language of this study leaves a lot to be desired. #schemaorg #structureddata #google #seo