... respond, this may affect the results of the survey. Therefore postal questionnaires should, where ever possible avoid being sent to these groups of people although this may result in a unrepresentative sample. "Some categories of people will be systematically under represented." (de Vaus 1996.) Another major problem of postal questionnaires is the low response rates. Some postal questionnaires do not achieve more than a 20% rate of return. (Simmons, 2001). However a higher response rate can be obtained by methods such as sending personalized letters written on official headed paper, sending written reminders, including a stamped addressed envelope, subtly suggesting a deadline and by offering incentives such as free gifts or entry in a prize draw. (Burns, 2000). The response rate also depends on the sample of the population used, the construction and layout of the questionnaire, and the topic of the questionnaire. The length of the questionnaire is also ...

See this essay or coursework document in full right now