Considering the characteristics of a research study will be helpful when trying to decide how much weight and credibility should be given to a study's findings. Remember that each research study contributes to an existing body of knowledge. Usually, more weight can be given to study findings that support and build on the findings of other research. If the findings are preliminary or unsupported by previous studies, it may be months or even several years before more definitive information becomes available. Often, the conclusion is that further research is necessary to prove or refine the results.
Medical research is conducted in many ways.
Some studies, known as clinical trials, are conducted with people, others are done with animals, and some are conducted with cells, genes, and other materials in laboratories. Before studies can be conducted with humans, research must first be conducted in laboratories and on animals. While the findings from these laboratory and animal studies often provide important insight into human biology and health, they cannot be directly applied to humans. Also, studies with a small number of human participants may provide interesting and promising clues, but large-scale studies that include many people are needed before concrete conclusions can be drawn. Part of assessing a study's credibility is noting who paid for it and whether these funders have anything to gain or lose from the research results.