by Lynn Halverson

Both quantitative and qualitative research can provide important answers and insights into research questions. Many times, however, a decision must be made to limit the costs, and therefore the scope of a research project.  How do you decide when to use quantitative research methods and when to use qualitative research?

A quick way to make an initial determination is to remember the following suggestions:

Use quantitative research when –

1. You need scientifically verifiable numbers
2. Your research questions can be answered with “How many…?” “What percentage….?” “Which segments of the population…?” or other answers that require counting

Use qualitative research when –

1. You need to understand motivation
2. Your research questions revolve around questions that start with “Why…?”

Assume that you are concerned about teen drinking and driving. You have developed five different print ads that you want to test with teenage drivers to see which approach is most effective. How would you test this campaign?

You could use quantitative research, such as an intercept survey, if you want to know the answers to the following questions:

Which of the five concepts was preferred by the greatest number of respondents?

1. Which did they like the least?
2. How did the other concepts rank in order?
3. Which of the pre-selected attributes (message, colors, size of font, photo) of Ad X did they like?
4. Which of the pre-selected attributes did they not like?

You could use qualitative research, however, to get at a deeper understanding of respondents’ reactions to the five concepts:

1. Which of the five concepts did respondents prefer?
2. What did they like about the concept they chose?
3. What did they not like about it?
4. How could they change this particular ad to make it more desirable/believable, etc.?
5. Why do they prefer Ad X to Ad Y?
6. Could we incorporate any of the positive characteristics in Ad X to make Ad Y better? How?

Whichever approach you choose, it is important to use researchers qualified in that particular kind of research.  Although qualitative research does not result in scientifically verifiable numbers, it is an important method of collecting data that can help you answer “Why” questions in your research.  Consequently, it is important to use experienced qualitative researchers for qualitative projects such as focus groups or cognitive interviews, and quantitative researchers when you need statistical reliability of your data.