Quantitative research is mostly conducted through closed-end surveys, where all subjects are asked the same questions and given the same response categories. Qualitative researchers are more likely to observe their subjects or to conduct more in-depth interviews than the surveys that are the stock-in-trade of quantitative research.
The quantitative researcher collects data or information that can be presented in the form of numbers, while the qualitative researcher is not limited to this type of information. The information used by qualitative researchers is much more likely to be words rather than numbers.
Qualitative research lends itself to more depth than quantitative research. In qualitative research, since quantification is unnecessary, fewer things can be studied, and this makes it more practical to study them more in depth. Since the information used in qualitative research does not have to be reduced to numbers, researchers can pay more attention to the rich and complex factors that comprise context. However, since the qualitative researcher is limited to relatively few cases, the cases he chooses to study may not be representative of the large number of cases he does not. Since the quantitative researcher can collect less information about many more cases, her data is more likely to be representative of all of the cases. Because the quantitative researcher is looking at many more cases, he must look at many fewer characteristics of each case, while the qualitative researcher can look at the rich multiplicity of factors in a small number of cases.
A quantitative researcher is much more likely to use his data to test a hypothesis that he has declared ahead of time. Researchers are more likely to do qualitative research on new questions that have been addressed by relatively little research. Quantitative research tends to be confirmatory, whereas qualitative research tends to be exploratory. Qualitative research is more likely to generate than to test hypotheses.