What criteria should be used to determine public relations practitioners’ choice of a channel and medium to communicate with a particular public? Why would a public relations practitioner be concerned with the criteria's information? How would this assist

What criteria should be used to determine public relations practitioners’ choice of a channel and medium to communicate with a particular public? Why would a public relations practitioner be concerned with the criteria's information? How would this assist? Why? Do you think every company is concern with this type of information? Why or why not?