Qualitative vs quantitative methods: two opposites that make a perfect match.

Researchers in sociology, psychology, nutrition, public health, and many other related fields have been engaged in a long-standing debate about the use of qualitative vs quantitative approaches to research (1-4). The two philosophies are as opposite as day and night. One, qualitative research, rests on the principle of subjectivity; it is often labeled soft and unscientific (5,6). The other, quantitative research, rests on the principle of objectivity; it is faulted for forcing individuals and human behavior into rigid categories (2,6). Qualitative researchers argue that in the absence of close connections with the object of study, results will be distorted. They seethe about the quantification or categorization of any qualitative findings. On the opposite end, quantitative researchers argue that in the absence of distance between the researcher and the object of study, results will be distorted. Quantitative researchers let their data speak for itself, with no self-involvement or judgment other than what the numbers reveal. Researchers quickly joined camps and considered any mixing of the two methodologies as misguided and, most of all, not pure (7-12). Yet being pure often means being inflexible. How can we study human nature, as infinitely varied and in constant motion as it is, when we are locked into rigid ways of thinking? TWO OPPOSING PHILOSOPHIES The heart of the qualitative-quantitative debate lies in the two methodologies’ fundamentally different philosophies. The essence of qualitative research is to capture life as it is lived. Qualitative researchers watch people in their own settings and interact with them on their own terms (13), believing the best way to understand a phenomenon is to study it in its context and become immersed in it (14). They perceive quantitative research as limited in nature, studying people in artificial settings and looking at a small section of reality. They argue that human experience cannot be described using numbers or adequately explained by manipulating, measuring, or controlling variables. Qualitative researchers call for flexibility. Instead of developing a structured survey with fixed questions and response categories, they allow the questions to emerge and change as they become more familiar with the subject area (2,14). In contrast, the tenet of the quantitative philosophy is objectivity gained through enumeration, aggregation, and causation (15). Kerlinger was quoted as saying, “There’s no such thing as qualitative data. Everything is either 1 or 0” (14). Knowledge means measurement, cause and effect, and reductionism. Quantitative research design is a detailed plan of operation with predetermined hypotheses (16). It uses statistical sampling techniques to survey representative samples and allow generalizations to the population being studied. Quantitative researchers pride themselves in being unbiased, taking an outside and objective view to studying the subject at hand (6). They criticize qualitative research for being biased; being shaped by the prejudices, views, and beliefs of the researcher as well as study participants; and being too particularistic, focusing too closely on the individual and failing to make connections to larger situations. As we examine the two opposing philosophies, the value of combining both qualitative and quantitative methods becomes evident. What better than to be able to explain human behavior by collecting the rich descriptive detail from qualitative data R. AbuSabha is executive director of the Health Research Science Board and M. Woelfel is director of the Evaluation and Analysis Unit in the Division of Nutrition, New York State Department of Health, Albany, NY. Address correspondence to: Rayane AbuSabha, PhD, RD, Wadsworth Laboratories, Empire State Plaza, Room E-275, P.O. Box 509, Albany, NY 12201. E-mail: rxa06@health.state.ny.us Copyright © 2003 by the American Dietetic Association. 0002-8223/03/10305-0001$35.00/0 doi: 10.1053/jada.2003.50129 COMMENTARY