Research 201: A Basic Introduction
© Brian Brown 1999-2000. All rights
reserved.
Measurements in
Research
 |
Researchers often attempt to quantify or measure things. For example, researchers might try to find out how many people watch TV3 news in NZ. |
If you look at this from a practical point of view, it is impossible to determine, as it would require monitoring every household that has a television set that is turned on at 6pm each evening. We don't have enough researchers to do this.
We think of all the viewers in NZ as a population. It is however too large for us to measure. So, we take a small number of viewers, called a sample. The viewers in the sample are generally randomly selected.
Why do we randomly select a sample from a population? Think about this for a moment. If we selected a group of people from the same area, perhaps from a rich affluent area, this may not be typical of the population at large, and as a group, may indeed have different viewing habits compared to the "average" New Zealander. One way of picking them could be by random selection from the electoral roll, telephone book, or other such lists.
Once we have our sample, the next step is to define an instrument that will accurately measure what we wish to measure. For our purposes, let's choose a telephone survey and ring each person in the sample and ask them a number of questions.
What shall we ask them? Well, first, we want to know if they will participate in our survey. We inform them of what we are doing and let them know how many questions they will answer (it will not take that long). Another question would be if they have a television set, and if they regularly watch TV3 news at 6pm.
We have a small problem. What do we mean by regularly watch? So, we need to redefine this question so it is clearer. We might prefer to ask them which channel they watch at 6pm rather than if they watch TV3.
| What type of research is the above (which television channel viewers watch), qualitative or quantitative? |
| What type of research is the above (What happens to you when the lights go out. Dolly Magazine, Jan 99), qualitative or quantitative? |
Four Different Ways
of Measuring Things
The scientific research model has developed four
different ways of measuring things. These four levels of
measurement are
| Nominal Variable | Numerals or symbols are used to classify persons, objects or characteristics. For example, you might assign the value 1 to people who watch TV1, the value 2 to people who watch TV2 and so on. It does not imply that any one value is better than any other value. |
| Ordinal Variable | These are ranking according to value, normally from smallest to largest. For instance, we might place the annual salary of people into three categories, low, middle and upper. We then use the value 1 to signify low income, 2 to signify middle income, and 3 to signify upper income earners. In this instance, there is a clear ranking of status between each group. Other examples of ordinal scales are team ranking's (such as NPC ranking results) and contest winners (such as a beauty pageant). |
| Interval variable | This is an ordinal scale with equal values between points on the scale. An example is temperature. The interval scale has no true zero point, so you cannot say that a certain value is twice that of another value. Examples of interval measurements are temperature, IQ results, and personality scores. |
| Ratio variable | A ratio scale is the same as an interval scale, but includes a true zero point and thus allows comparisons to be made between points on the scale. For instance, someone travelling at 50mph is travelling twice as fast as someone travelling 25mph is. Other examples of ratio measurements are the number of hours spent watching television or the number of words in an article. |
| In the quiz shown below (from Lifestyle magazine, Feb/Mar 1999), what is the type of measurement variable being used (Nominal, Ordinal, Interval or Ratio)? |
Please classify the following as either Nominal, Ordinal, Interval or Ratio
Which television channel do you regularly watch?
TV1
TV2
TV3
TV4
PRIME
Please classify the following as either Nominal, Ordinal, Interval or Ratio
Which income bracket best describes your monthly income?
1. Below $20,000
2. Between $20,001 and $45,000
3. Above $45,000
Please classify the following as either Nominal, Ordinal, Interval or Ratio
[Answers]
