The Effect of Covering Letter Personalisation in Mail Surveys
Personalisation of mail survey covering letters may involve one or more of the following: including the respondent's name and address in the letter; using a salutation that includes the respondent's name (i.e. 'Dear . . .' rather than 'Dear respondent' or 'Dear householder'); an individually typed letter; an original rather than a copied signature; a handwritten note in the covering letter.
There are two justifications for personalisation, both drawing on the theory of social exchange. The first argues that, if potential respondents recognise the extra effort required to personalise the researcher's correspondence with them, they will be more likely to respond because of the social obligation to reciprocate the expended effort (Dillman 1978). However, this seems a rather tenuous rationalisation since it assumes that respondents are aware of the trouble the researcher has taken to personalise the survey correspondence. Why this should be so is by no means obvious; after all, as far as each respondent is concerned, only one letter has had to be personalised.