In the scientific community, there is great debate between qualitative and quantitative research methods. Despite the criticism that qualitative methods are interpretive and invalid as scientific evidence, the real discrepancy lies within the types of data that each method produces. Quantitative data measures quantifiable terms, such as "how much," "how long" and "how many," while qualitative data measures the reasons behind behaviour, such as the "how" and "why." While neither method is "better" than the other, there are advantages and disadvantages to both.
Qualitative research allows one to explore topics in more depth and detail than quantitative research. Also, qualitative research is often less expensive than quantitative research, because you don't need to recruit as many participants or use extensive methods. Another pro of qualitative research is that it offers flexibility as far as locations and timing because you don't need to interview a large number of people at once.
One major disadvantage of qualitative research is that it cannot quantify how many of your audience answer one way or another. This makes it extremely difficult to create any type of solid statistic. Another con is that you cannot generalise your findings. As opposed to quantitative surveys, qualitative research does not allow you to use your findings as a basis for a broader audience or the public in general.
One of the pros to quantitative research involves the fast speed that data can be collected. This data can also be analysed fairly quickly. In addition, using statistically valid random samples, a survey can quickly be generalised to the entire population. Another advantage involves the planning process for programs and messages. With the reliable, repeatable information that quantitative surveys can provide, a trusted set of statistics can give confidence when making future plans. Quantitative research can also be anonymous, which is useful when dealing with sensitive topics. Another major pro of quantitative research is that it allows you to generalise your findings beyond the participant group.
One con of quantitative research is the limited ability to probe answers. Also, people who are willing to respond may share characteristics that don't apply to the audience as a whole, creating a potential bias in the study. In addition, quantitative research experiments can be costly.