PR is a management function that identifies ,establishes maintains mutual beneficial relationships maintaining the goodwill of the organisation ,brand of a product or celebrity's image where the relationship varies differently in each sector being corporate,entertainment or media where the relation is shared between organisation and the public's on whom the success and failure depends accordingly.PR is defined as the process of communication which takes place internally or externally that flows one way so as too influence.
PR is based on knowledge of media markets and a network of contacts involving proper communication channels based on research solving complex problems,crisis and achieve success with the opinion and belief of key public's.
PR is always been a confusion about how it is different from marketing & advertising ,
Advertising & Marketing focuses on consumers alone where as PR focuses not only on consumers but other stakeholders like government ,regulator's,media,community members,shareholders,employees and others protecting their image .
PR is called the umbrella where other activities such as advertising and marketing occurs and takes place.
Everything is linked up with research ,hence research is very important ;if proper kind of research is employed it helps to work easily for a particular campaign better would be the chances of a proper evaluation would lead on a right track to measure the ROI and good Return of Investment would lead to increase in the credibility.