Quantitative vs. Qualitative Marketing Research

Author: Paul Richard McCullough
Published 1988 by MACRO Consulting, Inc.

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There are two basic approaches to marketing research: quantitative and qualitative. Quantitative research involves large numbers of respondents, typically 100 or more, and yields results that are representative of the total population. Qualitative research is generally done in the form of focus groups, that is, groups of six to ten respondents at a time carry on a group discussion which is led by a trained moderator. Another common form of qualitative research is in-depth one-on-one or two-on-one interviews.

Qualitative research has two primary advantages:

• It allows the moderator (or interviewer) to interact with respondents, i.e., the moderator can ask questions based on previous responses. This allows for in-depth probing of issues and yields great detail in response.
• It allows for interaction between group members. This interaction often stimulates discussion and uncovers issues unanticipated by the marketing team.

The primary disadvantage of qualitative research methods is that they are unreliable predictors of the population. That is, they can expand our list of possibilities, but they cannot (or should not) be used to identify the best of the possibilities.

Because of the advantages and disadvantages discussed above, qualitative research is appropriate for two uses:

• To generate ideas and concepts (lists of possibilities)
• To uncover consumer language in order to subsequently ask consumers the right questions in a way they most accurately understand

It is not appropriate for evaluating pre-existing ideas.

Quantitative research, on the other hand, has these advantages:

• The results are statistically reliable. That is, quantitative research can reliably determine if one idea, concept, product, package, etc., is better than the alternatives.
• The results are projectable to the population. That is, the proportion of respondents answering a certain way are similar to the proportion of the total population that would have answered that way if they all had been asked.

The primary disadvantage of quantitative research is that issues are only measured if they are known prior to the beginning of the survey (and, therefore, have been incorporated into the questionnaire).

Thus, quantitative research is appropriate when:

• The issues to be tested are known
• The language used by consumers to describe these issues is known

Generally, quantitative research is not appropriate as an initial learning phase, or as a method to develop creative ideas. Quantitative research is essentially evaluative, not generative.