Most scientific research will follow one of two approaches - it can be either qualitative or quantitative. Health care research is often based on quantitative methods in which, by definition, information is quantifiable. That is, the variables used in research are measured and recorded as numerical data that can be analyzed by means of statistical tools. The use of quantitative research in health care has several benefits.
The main strength of quantitative methods is in their usefulness in producing factual and reliable outcome data. After the effects of a given drug or treatment have been tested on a sample population, the statistic record of the observed outcomes will provide objective results generalizable to larger populations. The statistical methods associated with quantitative research are well suited for figuring out ways to maximize dependent variables on the basis of independents, which translates into a capability for identifying and applying the interventions that can maximize the quality and quantity of life for a patient.
Quantitative researchers are often accused of reductionism; they take a complex phenomena and reduce them to a few essential numbers, loosing every nuance in the process. However, this reductionism is a two-edged sword with a very significant benefit. By reducing health cases to their essentials, a very large number of them can be taken into consideration for any given study. Large, statistically representative samples that would be unfeasible in qualitative studies can be easily analyzed using quantitative methods.
Evidence-Based Health Research
Given the benefits of quantitative methods in health care, evidence-based medicine seeks to use scientific methods to determine which drugs and procedures are best for treating diseases. At the core of evidence-based practice is the systematic and predominantly quantitative review of randomized controlled trials. Because quantitative researchers tend to use similar statistical methods, experiments and trials performed in different institutions and at different times and places can be aggregated together in large meta-analysis. Thus, quantitative research on health care can build on previous studies, accumulating a body of evidence regarding the effectiveness of different treatments.
Evidence-based medicine, and quantitative methods overall, are sometimes accused of leading to "cookbook" medicine. Some of the phenomena of interest to health researchers are of a qualitative nature and, almost by definition, inaccessible to quantitative tools -- for example, the lived experiences of the patient, his social interactions or his perspective of the doctor-patient interaction. However, judicious researchers can find a combination of qualitative and quantitative approaches so the strengths of each method reinforce those of the other. For instance, qualitative methods can be used for the creative generation of hypotheses or research questions, adding a human touch to the rigorous quantitative approach.