I work with some machine learning methods in my job, in semiconductor field: usually we start from a data set, more o less big, we clean it through some criteria and algorithms and then run some algorithms, already available, to get a model of these data. Some times we get some good results many other not, So I'm wondering, what kind of job is a data scientist? what are his expertise, what are his knowledge of data he's working on, what are his goals inside the company? Should they develop (writing codes) specific methods for different work area?
There are all sorts of data scientists.
Depending on the size of the company, these roles can overlap. Many times, an employee is given a job title that does not match what she is doing (typically, "data scientist" for a job that is actually "data analyst".)