Qualitative research is a method for gathering data that employs the use of surveys and focus groups with the goal of understanding the attitudes and behaviour of the target group. It is looking for people to give their subjective account of an experience or idea. The researcher spends more time with the test subjects and generally tests fewer people compared to Quantitative research.
Quantitative research involves gathering statistical data; usually in the form of questionnaires and focussed interviews and usually involves using the Scientific Method to obtain information. If you have been called upon to fill in a document verbally or orally that asks you to rate on a scale of 1-5, you have participated in Quantitative research. Demographic information falls under this category: age, sex, occupation, area of residence, etc.
There is a tendency in the scientific community to give more credence to quantitative research, but this attitude is a mistake as both methodologies have their place in gathering research. I once assisted on a study that examined perception of crime and safety within a subject’s neighborhood as defined by them. For example, what you consider to be part of your neighborhood, I might not, even though we live next door to each other. When we looked at the answers to the questionnaire where people identified crime “hot spots” in their neighborhood, we found that there were some definite streets, houses and intersections that were widely thought to be centers of criminal activity. This would be considered Qualitative Data, but we also examined demographics as well: income, married status, sex, age, etc. because these two types of data support each other, fill out a more comprehensive picture and raise interesting questions about relationships between two sets of data. For example, is one age group more fearful of a particular area of town than another age group.
Both sets of gathering data are valid and useful, and many researchers employ both methods when studying a phenomenon.