D annan a simple guide to resarch writing indd

Validity and reliability
 
Validity addresses the issue of whether the researcher is actually measuring what they set 
out to do. There are four types of validity 
– each of which the researcher would ideally want 
to establish for the research instrument prior to administering it for the actual study. These 
four types are listed in Figure 5.1 below.
Reliability of a research instrument refers to the consistency or repeatability of the 
components of reliability. There are three types of reliability, as listed in Figure 5.2.
Interviews
 
Interviews and questionnaires are two of the most widely used primary data collection 
methods. Questionnaires have been dealt with in detail in the previous sections. The 
interview is a form of data collection that is very common in descriptive research such as 
surveys, and can be use to collect valid and reliable data in other types of research. In 
contrast to questionnaires, interviews generally tend to:
• Make greater use of open-ended questions
• Are associated more with qualitative, phenomenological-oriented research
• Make use of small, deliberately selected purposive samples.

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Figure 5.1: Types of validity
 
 
 
Figure 5.2: Types of reliability
 

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Direct, verbal interaction
 
The interview is unique because it involves the collection of data through direct verbal 
interaction (often face-to-face).
• The interview enables the researcher to follow up verbal leads and thus obtain more 
data and greater clarity.
• The interview situation also permits much greater depth than other methods of 
collecting data.
There are various types of interviews with the highly structured, interviewer-administered 
questionnaire and the structured open-ended, in-depth interview as opposite ends of a 
continuum.