The main advantage of telephone interviewing is from the researcher point of view.The number of different people can be reached in a relatively short period of time.From the respondents standpoint it would eliminate any discomfort that some of them would feel less uncomfortable disclosing personal information over the phone than face to face.
believe the only disadvantage to a letter is time:it takes time to write them and it takes time for them to arriveTo write a letter is easier than the emails because there is no need of any specific device while writing a letter and everyone can use this facility very easily.Same is the case with the receiver because no specific device is required to access the letter as everyone has a home.
Another biggest advantage of the letters is that the recipient of the letter can maintain the physical record of all of his mails.One does need to take pain of switching on the computer in order to read the mails or the letters of the beloved ones.Great Answer Not Helpful Report