Those that are comparing X-factors rating fall to DR Who rating fall, there is just no point in doing this, they are two very different genres, on two very different channels.
BBC 1 doesnt have to worry about live viewers in the way ITV does. As long as a high audience overal see it (inc. catch up, online or repeats) then the BBC will be happy. ITV on the other hand needs mass audiences that night, one of the reasons that ITV has a +1 channel. A viewer on the night is worth alot more to them than a viewer in a couple of days time online to ITV and advertisers.
Shows like X-factor are water cooler tv, they get big ratings in their main broadcast, which ITV need, as people dont want to be left out of the conversation the next day at work, when everyone is talking about it. This is why they are so important to ITV.
Dramas are no longer water cooler tv, people dont mind catching up with them later in the week. This is why you generally see dramas getting a bigger up shift in viewers when catch up is included. For a channel like BBC 1, as long as a large number of people eventually watch it, they dont care.
So though many see it as a bad sign that Doctor Who is no longer appointment tv,, as long as the ratings are high including all the various other way to watch it, they will be happy, over nights mean very little to them. However, for ITV it is alot more important, as same day viewers are more important to advertisers. In this sense as long as Dr Who makes up viewers by the finals, this is a much worse situation for ITV.
Mentioning appointment tv, this is the first year at work where there hasnt been a single conversation about the X-factor at work. Going forward if this is true everwhere, that will be a big concern for ITV.