There are many questions about health, illness and the effects of treatment where there are no clear answers. Knowing what the questions are makes it easier to say what future research studies should look at.
For example, there is no medical consensus on the best treatment for an enlarged prostate gland in men (benign prostatic hyperplasia, or BPH). The enlargement causes urinary problems such as increasing the number of times a man has to urinate, making the desire to urinate urgent, and reducing the flow of urine.
BPH is either treated with surgery, or by simply keeping an eye on things (known as watchful waiting). There is no convincing evidence that one is better than the other and it may be a matter of personal choice by the doctor or patient.
This is where research is important, by trying to understand which treatment works best and when.
The right research project
There is a benefit in repeating research if uncertainties remain. But if the answer is already known then it will probably be more important to move on and ask another research question.
Doctors, researchers and increasingly patients and the public review the research that has been carried out and try to choose research projects that look at important unanswered questions.
Research ethics committees are now asking researchers and others seeking approval for new trials to show that they have already reviewed previous research. If they do this, researchers are more likely to choose an appropriate research project and get an answer that will be helpful to patients.
Collecting together what is unknown
Researchers and scientists have, for centuries, made huge efforts to collect together what they know in medical libraries and more recently in electronic databases. Now researchers are collecting together what they are not sure about in the UK Database of Uncertainties about the Effects of Treatments (DUETs).
The main aim of DUETs is to help people decide which of the unanswered questions are most important, such as how prostate cancer should be managed.
DUETs identifies the need for future research using guidelines from the National Institute for Health and Clinical Excellence (NICE) and other publications which highlight gaps in knowledge. Researchers also have increasing interest in the questions that matter to people who are ill, their families, and others who care for them.