a) Length of questionnaire (respondent may not have sufficient time to answer)

b) Complexity of questions (respondent may not understand the question)

c) Sensitiveness (highly sensitive and personal/secrete issues)

d) Hypothetical (responding to hypothetical questions will be difficult to the respondent)

e) Threatening (enumerator may treat/influence the respondent so as to obtain desired response)

f) Leading (enumerator may lead the respondent so that he/she may not say what is actually what to say)