Quantitative data usually involves numbers and refers to information that researchers can measure empirically. They frequently begin by finding basic descriptive data, such as the frequency that a value occurs, the mean value, the median value and the standard deviation from the mean. Qualitative data includes words and language, including answers to open-ended questions and narratives. Researchers sometimes assign codes to certain words or ideas in order to find patterns and trends.
If you need to find out information based on measurable facts, you look at quantitative data. The scientific method guides quantitative data research. If you seek data based on observations and human experiences, qualitative methods are appropriate. Some forms of qualitative data involve researchers participating in the areas they are studying, such as anthropologists living among a group of people they are observing.
One way to determine whether researchers should use qualitative or quantitative data is to look at the purpose of the research. For example, if you want to examine whether a trend is developing, you might use quantitative research to count how many people use smart phones instead of desktop computers to surf the Internet. If your goal is to find out why people choose one method over the other, a qualitative survey might ask individuals to explain their preference.
A survey of 1,000 households might ask the subjects to choose the detergent they prefer from a list of five detergents, and how often they use it. The quantitative data received gives the researchers objective evidence about the popularity of a detergent and its frequency of use. Qualitative research on detergent use might ask the participants to describe how they use the detergent and relate their experiences with the product. Researchers could use both kinds of data to form marketing plans that tap into the widespread use of a detergent as well as why people like it.