Qualitative research seeks to find out the 'why', for example why someone acts in the way that they do, rather than counting how many times someone acts in that way. For example, you can find out why a group of high-school freshmen enjoy pizza for lunch versus meatloaf. You cannot, however, find out how many high-school freshmen like pizza versus meatloaf. Finding out how many would involve quantitative research.
Qualitative research is the complement of quantitative research which relies on large samples and counting. Qualitative research methods involve a smaller sample, and organizes the data into patterns.
The two methods can be used together to create a comprehensive study.
Qualitative research methods include