It depends on the type of page and the type of microdata. If it's a product page for example, you can get things like star ratings and pricing in Google search results directly.
microdata (schema.org) in itself does not provide better CTR. If the search engine (particularly Google) displays Rich Snippets based on microdata (or another form of structured markup e.g. JSON-LD) on your site, that will increase the likelihood that someone would click on your results but it is important to keep in mind, just because something is marked up in microdata, doesn't mean that it will generate a Rich Snippet in SERPS. Another item to consider is the semantic web and how microdata adds context and meaning to the items that are marked up correctly.
For my informal tests, micro data (the stars / reviews data) option I used had a big effect on serp CTR. I just did an article on our blog which showcases a serp study on the pharma serps (viagra) and there are several sites using schema.. Some of the best seo's work pharma..and if you see something there, there is a reason. Good luck! B