What is difference between human resources and public administration?

HR is another way of referring to a company's Human Resource department and a subset of Administration.  They are responsible for employee related matters such as hiring, firing, keeping records on performance reviews, pay increases, bonuses, health and dental insurance coverage, 401K plans, stock-based awards, employee profiles and so forth.Administration refers to operations within the company dealing with non-product related activities (such as retailing, manufacturing and distribution).  Administrative functions typically include accounting, HR (sometimes called Personnel), legal, IT, advertising, sales, marketing, security, maintenance, purchasing, real estate, public/investor relations and the like.