When the term was first coined it had a clear meaning - someone who was a statistician, and a programmer, and a subject matter expert. Someone who could, for i

When the term was first coined it had a clear meaning - someone who was a statistician, and a programmer, and a subject matter expert. Someone who could, for instance, write code from scratch to calculate maximum likelihood estimates, and use it to make predictions on real world data. The term got coopted by snake oil salesmen pretty soon after.