How we know

On our website, we offer you information about cancer and about making healthy choices to reduce your risk of getting cancer. Our health messages, cancer information and policies are based on scientific research. Here’s how we find and evaluate the research evidence.

Finding the evidence

We review the best available scientific evidence. We gather the evidence from:

scientific research published in medical and scientific journals
information from scientific conferences
respected organizations that review cancer-control science, such as:
World Health Organization and its International Agency for Research on Cancer
Health Canada and the Public Health Agency of Canada
Environment Canada
National Cancer Institute and National Institutes of Health in the US
Centers for Disease Control and Prevention
National Toxicology Program in the US
Environmental Protection Agency in the US

Perspectives from other respected organizations such as the American Cancer Society and Cancer Research UK are also considered. Where appropriate, we also consider information from the European Commission Environment Directorate and the European Environmental Agency.

Evaluating the evidence

To evaluate the evidence, we look at the big picture. Information and policies are generally based on many studies. This is called the overall body of evidence.

We evaluate the:

quality of each individual study
number of studies that have assessed the research question
consistency of the study results

For example, we ask: Do most of the studies come to similar conclusions? Why or why not? The overall conclusion from the body of evidence is called the weight of evidence.

Getting external expertise

We also consult experts (for example, healthcare professionals, scientists and researchers) to help us interpret research in their field of expertise. Sometimes we ask experts to provide technical expertise, help evaluate individual studies or consider the weight of evidence.

Last modified on: 26 November 2011