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Struggling with numbers can affect people’s attitudes to screening

by Misha Gajewski | Analysis

22 December 2014

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Why are so many of us frightened of being in a plane crash, but don’t think twice about getting into our car or eating a burger – despite the fact that these are far more likely to cause us harm?

The truth is most of us find words, stories or pictures easier to understand than numbers – which means that when information isn’t presented in ways we can relate to, we can end up thinking of certain risks as much bigger, or more important than others, even if that’s not strictly the case.

In fact, 4 in 5 adults in the UK have low levels of numeracy, according to the charity National Numeracy (which they define as below grade C GCSE level).

This has consequences. Lower levels of numeracy can affect a host of things, from our confidence to employability. And there’s a wealth of evidence that how we understand health information – especially written information, but also numbers – can affect the choices we make about our health or lifestyles, and so how healthy we end up being.

And studies show that people understand numerical information much better when it’s presented with visual explanations, rather than just the numbers on their own.

A new study our researchers published last week provides more evidence to support this challenge. The team found that people who answered a numerical question wrongly were also more reluctant to take part in bowel cancer screening, and felt more negatively about it.

Let’s look at what the researchers did.

The study

The researchers – based at University College London – sent out a questionnaire to people aged 45 to 59 in Northern England, which tested their numerical skills, as well as their attitudes and knowledge about bowel cancer and screening.

Out of the 964 people who returned the questionnaire, nearly half of them (46 per cent) got the wrong answer when asked which of the following numbers meant people had the biggest risk of getting a disease: “1 in 100, 1 in 1000 or 1 in 10.”*

The researchers found that those who got this number question wrong knew little about bowel cancer screening. This is important – understanding the benefits and harms of screening, is essential when making an informed decision about whether or not to take up bowel screening.

These people were also more likely to think bowel screening was ‘disgusting’, ‘embarrassing’ or feared an abnormal result.

Finally, those who’d got the number question wrong were also less likely to say they would be taking part in bowel screening when invited.

This all points to a need to provide better and more accessible information, and support to help people make informed decisions about screening, so that screening can be equally understood and accessed by all.

What’s the big deal?

Watch an animation about the bowel screening test on YouTube

Watch an animation about the bowel screening test on YouTube

In the UK the test used as part of the national bowel cancer screening programme is the Faecal Occult Blood Test (FOBT). The test is offered to people between the ages of 60 and 74 in England, Wales and Northern Ireland, and 50-74 in Scotland, and involves taking small samples of faeces at home, and sending them to a lab for analysis.

The test can detect early stages of cancer, and spotting bowel cancer early means treatment is more likely to be successful.

Unfortunately, the number of people who return their test is relatively low.

This study adds to our knowledge of what affects people’s chance of taking part in screening. Understanding these factors is important in working out how to increase bowel screening uptake.

Not Just Bowel Cancer

But it’s not just about bowel screening. According to National Numeracy, lower numeracy can affect a person’s health and wellbeing too. They point out that the Department for Education and Skills 2003 ‘Skills for Life’ Survey found links between respondents’ reported health and their numeracy levels.

And The UK Government’s Department of Business, Innovation and Skills have also published a recent report looking into the links between numeracy and with health.

Higher numeracy also brings other benefits, such as an increased likelihood of being employed, and having higher wages.

For example, the Organisation for Economic Co-operation and Development (OECD) – an organisation that “promotes policies that will improve the economic and social well-being of people around the world”, has published data showing that there is a direct relationship between wage distribution and numeracy skills.

What Now?

Lower numeracy is a problem that the UK is keen to resolve.

“It’s essential to increase people’s numeracy skills to improve their abilities to look after their health, navigate the healthcare system, and improve their general wellbeing,” said Hannah Cowan, from National Numeracy.

In the mean time Dr Samuel Smith, lead author of the Cancer Research UK study, hopes his team’s findings will lead to an improvement in how bowel screening is discussed with the public.

“That might be through targeted campaigns in deprived areas where low numeracy and literacy skills are more common, or through health workers discussing screening with people who might be inclined to ignore written information or think they don’t need to take a screening test,” he says.

We are also doing our part to help make information about health related issues more understandable.

We take on-street roadshows direct into more deprived areas, staffed with trained nurses, who can talk people through information about screening, symptoms or healthy living.

We also have a team of cancer nurses who talk to people on the phone and can answer questions about screening.

Our written information about screening is designed to be as accessible as possible, and studies like these help us know how we can refine our information even further to make it accessible and understandable for all.


*The correct answer is 1 in 10.


  • Smith, S., et al. (2014). The associations between objective numeracy and colorectal cancer screening knowledge, attitudes and defensive processing in a deprived community sample Journal of Health Psychology DOI: 10.1177/1359105314560919

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