How to read the evidence

With so much health information available to us, whether through the internet, newspapers, television, social media or shared amongst family and friends, it can be difficult to know what you can trust to be reliable and accurate.

There are often different or conflicting claims about what is or isn’t good for us, or what is or isn’t helpful for treating or living with cancer.

Here, we bring together a range of guidance to help you to feel more confident in reading and recognising evidence-based health information. 

If you have any concerns or are still feeling uncertain about the evidence behind anything you have seen or heard in the media, speak to your doctor (or, if you have one, your breast cancer nurse). They will be up to date with the latest evidence and will be able to advise you as to what is trustworthy and what may or may not be relevant to you and your situation, allowing you to make informed decisions about your health and care.

Tackling the headlines

Whether in the newspaper, on the morning news, on your twitter or Facebook feed or when scrolling through Google, you are likely to come across a wide range of health-related headlines, which may or may not be based on reliable evidence.

Health related headlines and news stories across the media often relate to complementary or alternative therapies, foods or diets linked to health and disease.

It is important to know whether or not these are based on scientific evidence before using the information you read or hear about to make any decisions about your treatment, health or lifestyle.

Things to consider

Remember: the purpose of a headline is to grab your attention.

First things first, it is a good idea to follow the headline to the article, or to listen to the report in full, to identify the source of evidence behind what is being reported. For example, if there is a claim of a new treatment or therapy helping to control secondary breast cancer, where is the evidence to back this up? Has a research study been carried out and is this described in detail?

Often, news stories and reports fail to mention information which provide clues as to the strength of the evidence. Let’s say a new treatment has hit the headlines. Key details which are often missed in reporting include:

How well the new treatment was found to work when compared to another. A new treatment may be reported to be effective in treating, for example, sickness. This information alone sounds very positive. However, it is much more useful and informative if its efficacy (i.e. how effective it is) is compared to another anti-sickness treatment. This may reveal that the new treatment is much more effective than current treatments. On the other hand, it may show that, despite being successful in treating sickness, the new treatment is not as good as what is already available.

If the treatment resulted in any unwanted or negative side effects. A new treatment may be extremely effective in treating a disease or health condition, but it may cause such significant side effects that patients are not able to tolerate it. Though these are very important considerations, they may be missed from headlines or news stories looking to give a ‘positive spin’.

If it was possible to tell whether the results were due to chance. Some studies or news stories may report figures or statistics which sound very positive. For example, patients taking a new painkiller may have reported less pain than those taking another painkiller. However, it is important to know whether this difference is ‘statistically significant’. If it is not statistically significant, we cannot be sure whether the observed difference was so small it may have simply been due to chance.  

In general, it is a good idea to be critical and to try and dig a little deeper when you come across headlines and news stories. These considerations also hold true for complementary therapies, supplements and diets which frequently hit the headlines, often in relation to cancer.

The media is a valuable source of health information but be aware that some things you read may be in fact be misinformation or evidence that is reported in a way that bends or only tells the partial truth.

Sometimes, different headlines or news stories contradict one another. For example, there is research to suggest that drinking red wine can help to reduce your risk of breast cancer and that, in moderation, it is good for the health of your heart. On the other hand, news stories have also reported that drinking alcohol increases your risk of developing cancer. This can be extremely confusing, especially when there is evidence to support both claims. In these situations, it is best to look to the advice of medical experts, whose opinions are often asked for in news articles and in radio and television coverage. They are able to bring together the evidence and provide guidance on how this should be interpreted in real life.

The NHS ‘behind the headlines’ website helps you to consider the evidence behind the headlines and news stories you might come across. Their website lists recent health news headlines, categorised by health condition, and explains the science behind the story in a way that is easy to understand. 

Above all, always look to the evidence and, if you have any doubts, speak to your doctor or nurse.

Research studies: The basics

A research study is a ‘catch all’ term. There are lots of different types of research studies which are carried out to investigate and provide evidence for or against something. You may come across lots of different study types and terminology in the health information you access.

Different types of studies are used to answer different types of research questions.

Observational studies

This type of research follows people in their every-day life, observing the effect of something over time. There are several different types of observational studies.

Cohort studies. These studies follow a large group (a ‘cohort’) over time to find out how often something occurs (e.g. a particular disease) and whether there are any risk factors for developing this. Some people will be exposed to something the researchers are interested in (e.g. exposure to sunlight or alcohol intake) and others will not. After a certain amount of time (often many years), they look to see if an effect is more likely in one group than the other, e.g. whether participants with high exposures to sunlight or alcohol are more likely to develop cancer than those who are not. This is the ‘prospective’ approach, meaning researchers look forwards and what will happen.

Other cohort studies are ‘retrospective’. This means that researchers take participants who have already developed the disease they are researching and look back at their history to try and identify risk factors which may have led to this.

Case control studies. These studies take a different approach in that they compare people who have a particular disease or condition with those who do not. These participants otherwise share very similar characteristics e.g. gender, age, ethnicity. Researchers are then are then able to look back at participants’ past to investigate the potential causes and risk factors which may have to led to them developing this disease or condition.

Cross sectional studies

Rather than following participants over time, a cross sectional study looks at a ‘snap shot’ in time. A good example of this type of research is a survey. Surveys gather facts and opinions as a one off, giving information relating to a single point in time. These studies are therefore much quicker to carry out and can be useful for providing information about how common a disease is, but they can’t provide evidence for more complex questions such as what causes a disease or how effective a treatment for a particular disease is.

Randomised controlled trial (RCT)

This sort of study is conducted to find out how effective a drug, treatment or therapy is by comparing two groups.

One group of people (the ‘treatment group’) takes the new drug or therapy. The other group (the ‘control group’) do not take the new treatment. They may take the current treatment or no treatment at all. Some trials use a ‘placebo’ treatment such as sugar pills, which are designed to look like the real treatment. This means that participants do not know whether or not they are taking the real treatment.

Participants are assigned to these groups at random, to make sure that there are no other factors which might influence the results. For example, if doctors were able to choose which group their patients were assigned to, they may be more likely to choose the group where they will receive a new and potentially promising treatment.

Where researchers are looking to find out how effective something is, RCTs are the ‘gold standard’ of research studies. This means that the evidence from an RCT is considered to be of the highest quality.

Clinical trials

A clinical trial is a study involving human volunteers (participants). These are carried out once researchers and doctors have researched the drug or treatment, usually in animals, and have evidence to suggest that it could be better than what is currently available.

There are different phases of clinical trials which you may come across when reading about research and treatments.

Phase 1

In the first phase of a clinical trial, doctors and researchers want to find out if the drug or treatment is safe in humans and to explore what doses they are able to give without causing any significant unwanted side effects or issues.

In this phase of the trial, there is a small number of participants involved. Everyone will receive the treatment, though they may be given different doses in order to compare effects.

Phase 2

At this next phase, doctors and researchers are looking to find out more about how well a treatment works. With cancer treatments, they may be looking at whether they work in a specific type of cancer. This time, participants will receive different treatments and be compared.

This phase involves a larger number of treatment and usually runs over several years.

Phase 3

To progress to a phase III trial, the treatment must have been proven safe and effective within a phase II trial.

The next phase focuses on comparing the new treatment with the current standard treatment. Doctors and researchers want to know whether the new treatment works better that what is already being used and to compare the side effects experienced. These trials involve thousands of participants and can run over a number of years.

Phase 4

Sometimes, a drug or treatment can be approved after a phase III trial and doctors may start prescribing it to patients. However, research may continue to explore what happens when patients are taking this new treatment as standard. Doctors may want to know more about the efficacy of the treatment, such as what happens at different doses, when the drug is taken at different times, or in different combinations. This happens within a phase IV trial, which can again involve thousands of participants and over many years. This time, doctors are not concerned with comparing the new treatment to another; all participants will receive the new treatment.

Reading research: What to look out for

As well as looking out for the key details which are frequently missing from reports of health information and research in the media, there are some more specific things to consider when reading reports of research studies. Bearing these things in mind will help you to cast a more critical eye over reported research and get an idea of how reliable or trustworthy the information is.

The size of the study. How many people were involved? Evidence for the effectiveness of a treatment in a study of 1000 people is much stronger than evidence from a study of, say, 50 people.

Humans versus animals. Were human participants involved?If a health claim you come across is linked to a research study, check to see whether the research was conducted in human participants or instead used animals or animal cells. Though research involving animals is a vital first step before it can progress to involve humans, the effects of a drug, therapy or food which are seen in animal cells may not be the same when tested in humans.

Funding. How was the research funded? If the research has been funded by an organisation or company, is it in their interests for this story to be told in the way it is being told? E.g. if a drugs company has funded the study, there is the possibility that researchers may be biased towards (more likely to report) a positive effect of the drug in question.

Full report of the research. Is this research from a completed study? Some articles, news stories or websites refer to research presented at a conference and may therefore be based on what is called a ‘conference abstract’. This is a short summary of the research, usually giving few details about the researchers’ methods, making it difficult to judge how well the study was carried out. Sometimes, studies presented at conferences are still ongoing, meaning results are still being gathered and it may be too early to be able to make conclusions from the evidence available.

The NHS provides further guidance on how read health news based on scientific research.

Health information websites

As well as headlines and articles, there are also lots of health information websites containing a wide range of health information and guidance. Whilst these can be extremely useful sources of information, some websites may not be accurate, credible or evidence based.

Before searching for guidance or answers on health information website, or making any decisions based on what you have read, it is a good idea to consider the following;  

  • Author. Who has written the information? It is a good idea to look for health information on websites associated with health charities, hospitals or educational organisations such as medical schools and universities. These are more likely to be professionally reviewed and evidence based. Lots of these sorts of websites provide details of who has reviewed their content, such as doctors, nurses and medical advisors. This provides further reassurance that the information you are reading is professionally approved and has come from an evidence-based source. Look for contact details at the bottom of web pages. Websites should provide a point of contact for users to get in touch with them. Some websites also provide details of who has written their content within an editorial policy on one of their pages or include an ‘about us’ page. If you are unable to get a sense of who has written the information on a website, be wary of what you are reading.
  • Sources & references. Where has the information come from and on what evidence or research is it based? Reputable websites (i.e. those with a good reputation for providing quality health information) will provide details and links to studies and sources of evidence and information on which they have based their content and guidance. Journal articles and medical textbooks are very reliable sources, as well as websites of other well-known health organisations or educational institutions (e.g. universities and medical schools).
  • Date of publishing or date of last review. Is the information recent or has it been recently reviewed? If this is not indicated, it is possible that the information you are reading is out of date and may no longer be relevant.
  • Funding. Is the website sponsored by a company or organisation? If so, can you trust that the information you are reading is not biased towards their services? (i.e. the information is written in a way which benefits or promotes them).

Other things to bear in mind

Whilst online forums and support groups can provide valuable information and support in the form of shared experiences of others, remember that personal stories or experiences are not the same as evidence-based information and should not be a replacement for the guidance of medical professionals.

Medline provide a range of further useful guidance on healthy web-surfing and online health information.

If you have any doubts, questions or concerns about anything you have read online, speak to your doctor (or, if you have one, your breast cancer nurse).

Page last updated: April 2020