All of our guides are reviewed by their authors or editors at regular intervals. We send out the guides to authors and editors approximately every 24 months and we are in touch with our authors in between times to check whether any updating is required. Also, immediately we are aware of new evidence or guidance that will affect a guide, we initiate a review of that procedure by the author or editor; some guides have been updated twice a year to incorporate such changes. All new guides, updates and question banks are subjected to double-blind peer review.