Microsoft Word research method fm doc

3. Effect of the interview on the informant:
This is a possible factor in all interview situations. The informant may mistrust 
the intention of the interview and dodge certain questions or give misleading 
answers. For example: in a survey on alcoholism you ask school children: 
‘Does your father sometimes get drunk?’ Many will probably deny that he does, 
even if it is true. Such bias can be reduced by adequately introducing the 
purpose of the study to informants, by phrasing questions on sensitive issues in 

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Research methodology 
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a positive way, by taking sufficient time for the interview, and by assuring 
informants that the data collected will be confidential.
It is also important to be careful in the selection of interviewers. In a study 
soliciting the reasons for the low utilisation of local health services, for example, 
one should not ask health workers from the health centres concerned to 
interview the population. Their use as interviewers would certainly influence the 
results of the study. 
4. Information bias:
Sometimes the information itself has weaknesses. Medical records may have 
many blanks or be unreadable. This tells something about the quality of the 
data and has to be recorded. For example, in a TB defaulter study the 
percentage of defaulters with an incomplete or missing address should be 
calculated. 
Another common information bias is due to gaps in people’s memory; this is 
called memory or recall bias. A mother may not remember all details of her 
child’s last diarrhoea episode and of the treatment she gave two or three 
months afterwards. For such common diseases it is advisable to limit the period 
of recall, asking, for example, ‘Has your child had diarrhoea over the past two 
weeks?’