Know Your Chances is an accessible and empowering text that teaches lay audiences how to navigate the often-intimidating territory of quantitative claims about risks to health. It helps readers to be shrewd consumers of health statistics they encounter in public service announcements, the media and pharmaceutical advertisements. The authors assert that with the basic level of understanding offered by the text, well-informed lay people can critically engage with ‘the numbers behind health messages’ and make their own assessment of potential risks or benefits to their health.

While Know Your Chances helps readers to understand concepts like risk, study design and survival rates, it is not a biostatistical primer. It focuses on training readers to use quantitative evidence to understand their own health risks and to decide whether or not they themselves should adopt particular health behaviours such as cancer screenings, smoking cessation or pharmaceutical treatments. The text is intentionally written in an accessible and conversational style, avoiding the use of jargon and providing clear explanations of necessary technical terms. The text is also interactive, with short ‘quizzes’ to check the reader's understanding of each point. It also appends several helpful resources, including a glossary, a fraction-ratio conversion chart, a risk chart and a list of credible sources of health statistics.

The authors have organized the text into four sections that help readers critically assess various aspects of health claims. Part One helps readers understand the definitions and appropriate uses of risk statistics and introduces the risk charts the authors have developed to compare mortality rates for various diseases by age, sex and smoking habits. Part Two prepares readers to critically interpret claims about modified risk, i.e. claims that a certain drug or health behaviour will change your risk for a certain condition. Part Three guides patients through the comparison of potential benefits with potential costs and side effects. Lastly, Part Four encourages readers to develop a ‘healthy scepticism’ about the political, economic or even scientific agendas that may underlie statistical information produced by researchers, drug companies and public health agencies.

While Know Your Chances remains apolitical in its discussion, it subtly challenges the power structures of contemporary health and medicine by giving patients the tools and language they need to engage critically with the various actors attempting to influence their health behaviour. The authors' clear confidence in the reading public's capacity to understand and engage with their own health risks make for an encouraging and accessible text.