Because an episode could be recut and the duration altered lots of things about that episode have the potential to change between versions. So the segments / running order / music played and contributors might change which is why they were modelled at version level. Or the episode might be recut to make it suitable for a younger audience and because “Children’s” is a genre the genre was set at version not episode level. And the same for formats. It meant that Match of the Day in its entirety was not assigned to the Sport – Football genre but every version of every episode of every series was. In the green box we propagated genres and formats up from versions, through episode to series and brands just to make it possible to build useful aggregations. But it was all a bit of a workaround. These days the PIPs model has changed and things like genres, formats and contributors are assigned at the top level and cascade down in an “inheritance with override” fashion. So an episode looking for its genres will look to see if it has any genres directly assigned and if it doesn’t will look to its parent and onwards and upwards.