2.2. Ensuring measurements are valid, reliable
and unbiased
When you are thinking about measurement as it relates to variables,
you also need to think about other issues. For instance, you should
ask yourself:
How accurate or unbiased
are my measurements?
How reliable are my measurements? (An average
of repeated measurements is usually more reliable
than a single measurement.)
Consider again the characteristic ‘intelligence’. The
table below outlines how your measurements could be valid,
reliable and unbiased?
Ensuring the language that you use does not affect your
measurements
The language or terms you use can prejudice the response to questions.
Consider, for instance, how responses to a survey might change if
the word ‘problem’ is substituted for ‘crisis’,
or if ‘termination’ or ‘murder of the foetus’
is substituted for ‘abortion’. Your choice of language
can bias a response by suggesting to the respondent which answer
they think is correct. It is, therefore, important that the language
and terms you use are neutral.
Let’s look at an survey in which the variable used to define
a characteristic (in this case what is ‘in’) was criticised
as being both biased and invalid.
SCENARIO
The company Levi Strauss conducted a survey across
university campuses in the US[3].
The students surveyed were provided with a list of clothing
items and were asked to select what was 'in' that year.
The list consisted of:
Levi's 501 jeans
T-shirts with graphics
1960s-inspired clothing
Lycra/spandex clothing
Overalls
Patriotic-themed clothing
Decorated denim
Printed pull-on beach pants
Long-sleeved hooded T-shirts
Neon-coloured clothing
Levi-Strauss used the results of the survey in a marketing
campaign.
In each question below a statement is made about the
survey. Decide whether the statement suggests aspects
of the survey were
