Table 1 Facebook advertisement settings

Campaign objective

We selected ‘traffic’ to ‘Send people to a destination, such as a website, app, Facebook event or Messenger conversation’

Campaign budget optimisation

‘CBO may not spend your budget equally for each ad set. For example, if you have two active ad sets in your campaign, we might spend 90% of your budget on one ad set if that’s how we can get the overall best results.’ We turned this off as we did not want Facebook putting more budget behind ‘best performing’ ads, as we were looking for diversity and not just sheer volume of people

Automatic versus manual ad placements

We began with automatic placements whereby Facebook would decide where (e.g. main news feed, side bar, messenger) and on which platform (Facebook vs Instagram vs ‘audience network’) the adverts would be displayed

We subsequently changed this to manual placements and removed: messenger, audience network, marketplace, video feeds, and group feed placements. This was after an initial review showing that the proportion of impressions converted to link clicks was particularly low on messenger

Optimisation for ad delivery

Initially we selected ‘Daily unique reach – We’ll deliver your ads to people up to once a day’ on the basis of preferring the advert to go to a wider audience fewer times rather than targeting those most likely to click on a link. However, after 10,000 impressions and no link clicks, we changed this setting to ‘link clicks – We’ll deliver your ads to the people who are most likely to click on them’