Human element plays an important role in the application of big data. Though data science is based upon business analytics, it is different from business analytics. Data science collects data and other information from different systems and then asks many different questions. To know more about whether it is necessary to include data scientist when a company is deploying big data solutions or not, go through the article by Daniel Kusnetzky, software engineer and product manager in Kusnetzky group.
http://www.zdnet.com/the-human-element-is-critical-in-applying-big-data-7000028983/