This Core Outcome Set (COS) will outline which outcomes should be measured, as a minimum, in all future clinical trials assessing treatments for adults with epilepsy.

It will be developed using standardised methods used to establish consensus as outlined below.

Stage 1 (all participants) - An online survey will be sent to healthcare professionals, epilepsy researchers, adults with epilepsy, their carers, and members of patient advocacy groups. The survey will be completed twice. The first time the survey is completed, participants will see a list of outcomes and be asked to rate how important it is that each outcome is included in the ‘Core Outcome Set’.

Around 4-8 weeks later, the survey will be completed again, but this time each participant is given the chance to change their rating, after seeing the responses of other participant groups. This process is called the modified Delphi method and is now widely used in the development of 'Core Outcome Sets'. It is advantageous as it maintains the anonymity of participants, allows unrestricted expression of opinions, and consideration of others' views when voting. It therefore helps to reduce the influence of dominant personalities and the effect of participant status on the results.

Stage 2 (some participants) - It is predicted that not all outcomes will be agreed on during Stage 1. Some participants that have completed Stage 1 will be invited to take part in a half-day online consensus meeting to discuss the undecided outcomes in more detail. The aim is that at the end of this meeting there is agreement on which outcomes should be included in the adults epilepsy 'Core Outcome Set'.

Stage 1 and 2 will take place in Spring 2022.

The following video helps explain what a Core Outcome Set is, using asthma as an example: