National Breast Cancer Coalition

Research and Evidence

The Scientific Method


The steps of the scientific method are to:

  • Ask a Question
  • Do Background Research
  • Construct a Hypothesis
  • Test a Hypothesis by Doing an Experiment
  • Analyze  Data and Draw a Conclusion
  • Communicate Results

It is important in evaluating research to think about how the hypothesis was tested - was it done in a fair and unbiased way? Was only one factor different between the two groups? Or were there several differences that may explain the results? Also, look to see if the research is communicated in a peer-reviewed journal, meaning that other scientisits have read and evaluated the research, before agreeing to have it published.

Research is the search for knowledge. It is collecting information on a topic using a specific method, called the scientific method to establish facts. The scientific method is a way to ask and answer scientific questions by making observations and doing experiments. The research can be done in a laboratory, in a clinic involving groups of people, or even in a library looking through old records.

But all kinds of research must follow the set of steps outlined in the scientific method, to be considered reliable. 


What is evidence?

Following the scientific method produces scientific evidence, a collection of observations that goes towards supporting or rejecting the hypothesis. The scientific method is used to collect evidence in a systematic way in an attempt to avoid bias, or unreliable conclusions, such as those drawn from anecdotal evidence.

Scientists defend their claims at scientific meetings when they present their research, or through publication of their research in scientific journals. Research results must be reproducable, and new findings are often not accepted within the scientific/medical community until found several times by different research groups.

Not all evidence is equal. Some evidence is considered stronger because the research methods used make us more confident in the accuracy of the findings. Confidence in research results can vary based on the type of research study and the research design. Read about different types of research studies.

Why is research important?

What we know about breast cancer evolves over time as more and more research is done asking the important questions about how it develops, how we might prevent it, and which treatments are most effective for which patients. We want breast cancer care, and all of health care, to be based on the strongest evidence of what will work and what will be safe.

An example to show why research is important – research led to a dramatic change in how breast cancer is defined and now treated. Back in the 1980s it was assumed that all breast cancers were the same.  But laboratory studies began to indicate that breast cancer was not a single disease. Researchers found that there were sub-types of breast cancers that could be identified by their differing expression levels of genes ("molecular profiling"). This became important because identifying the sub-type of breast cancer can be used to predict how a patient will respond to a particular treatment. This finding dramatically changed how breast cancer is treated. Instead of assuming a larger tumor will be more likely to metastasize and treating bigger tumors more aggressively, it is now recognized that the different types of breast cancer need to be treated with different therapies and bigger doesn't always indicate a more dangerous tumor.