Deductive reasoning, which begins with general information and moves toward more specific information, predominates in quantitative studies. The researcher uses collected specific data to deduce the validity of a given hypothesis. Statistics serve as a basis of judgment for the general statement of the researcher's theory. No hypothesis is necessary for qualitative research, which uses inductive reasoning, moving from the specific to the general. After choosing a topic, the researcher conducts studies to learn about individual experiences. The findings are used to inductively formulate a general theory based on the specifics of the research.
Quantitative research methods rely on numbers and surveys to form the backbone. Researchers gather data from a statistically significant sample group on a set of questions related to their hypothesis. The end result includes written analysis, but the centerpiece of the findings is the numeric data. On the other hand, qualitative research consists primarily of text. The researcher examines first- and secondhand texts and conducts interviews with individuals or relatively small groups. The work of qualitative research rests on reading, writing, talking and listening. The final product will typically be prose text.
Quantitative research needs a large and random sample group because the quality of the research hinges on the data. The sample must reflect the total population, and the study should include controls and variables similar to a science experiment. Because qualitative studies make generalizations from analysis of a small sample, the validity of the research rests on the researcher's ability to obtain quality information and skillfully construct her findings. The audience of the research must be aware of how and when the findings can be generalized.
The reliance on statistics and charts can make quantitative analysis prone to overlooking key details of the particulars. When all information is forced into a set of predetermined parameters, the causes and connections of some of the individual outcomes may not be apparent. In contrast, the focus of qualitative research on individual subjects can put the research in danger of missing broader connections. Without sufficient analysis, the findings may favor causes present for the subject but not applicable more generally.