Research methodology
38
The variables to be studied are selected on the basis of their relevance to the objectives of
the investigation.
The initial list is usually too long
It has to be pruned to facilitate the collection and processing of the data.
Once
the variables are selected, each of them should be clarified. There are two aspects to
be considered.
1. Clear definition of variables in terms of
objectively measurable facts (i.e., operational
definition) - this was repeatedly mentioned (addressed) in the above examples
2. The
scale of measurement to be used in data collection.
Unless the variables are clearly and explicitly defined, there can be no assurance that, if the
study is performed by a different investigator, or repeated
by the same investigator, similar
findings would be obtained.
The following example shows the different definitions (two different definitions) given to
"obesity".
The two kinds of definitions are: conceptual and operational. The conceptual definition is
often akin to a dictionary definition.
e.g.
“ Obesity” may be defined as:
“ excessive fatness”, “overweight”, etc.
In contrast, the operational definition is heavily influenced by considerations of practicability. “
Obesity”, for example, might be operationally defined as: “
a weight, based on weighing in
underclothes and without shoes, which exceeds, by 10% or more, the mean weight of
persons of the subject's sex, age and height (in a specified population at a specified time)".
Dostları ilə paylaş: