What are evidence uncertainties?

The JLA definition of an evidence uncertainty is that:

  • no up-to-date, reliable systematic reviews of research evidence addressing the uncertainty exist
  • up-to-date systematic reviews of research evidence show that uncertainty exists.

Systematic reviews are based on worldwide searches for reliable, relevant evidence. They are comprehensive summaries and analyses of comparable published and unpublished studies of effectiveness, prepared by a team of authors.  Systematic reviews are used to inform health and social care service development, policy development, and research.

Many PSPs now extend their scope beyond identifying and prioritising simply 'treatment uncertainties' and include other healthcare interventions like prevention, diagnosis, rehabilitation, care, and service organisation and delivery.  The JLA recognises that a systematic review may not always be the best or most reliable source of evidence for every topic area or type of uncertainty.  Many of these other areas will require different evidence checking, extending beyond searching for systematic reviews.

The methods used by each PSP to check current and relevant evidence should be transparent, agreed with the PSP Steering Group and JLA Adviser, and clearly documented on the JLA's Question Verification Form.  There is a template for the Question Verification form in the Templates and useful documents section.  A PSP's completed form should be published on the JLA website as soon as it is agreed, to ensure transparency about the PSP's scope and progress.  There is more information about evidence checking later in the Guidebook.  The JLA website shows examples of what PSPs have published about their evidence checking, including from the Bleeding Disorders PSP and the Anaesthesia (Canada) PSP.

More detailed information about systematic reviews and fair tests of the effects of treatments is available in the James Lind Library.  Further information is also available at www.testingtreatments.org