Series 4 of Doctor Who begins on the 5th of April 2008 and ends on the 5th of July the same year. Let's dive straight into the stats, as some interesting things are starting to happen here. But first, the 2007 Christmas Special.
"Voyage of the Damned" features the Titanic and Kylie Minogue. It's questionable which of these is more responsible for the success of the programme, but successful it is, netting 12.2 million viewers on the night and 13.31 million over the next 7 days, indicating a Timeshift of 8.3%. Which brings me back to Series 4.
The average Timeshift for this series has increased to 10.5%, which means that on average only 90% of viewers are watching this on first broadcast. In fact if we look at individual episodes we can see that in 6 cases the Timeshift is over 10% (and on one - "The Stolen Earth" - over 15%). This is not unique to Doctor Who, but indicates that in the latter half of the first decade of the 21st Century, viewing habits are undergoing a big change. People are starting to take advantage of off-air recording more and more. It is becoming less important to watch something on the night, unless it is an Event that you want to talk about the next morning, or phone-vote on the night (such as Strictly Come Dancing, or The X-Factor). Doctor Who is no longer one of these Events. In fact arguably it never was, and was always just a programme that people enjoyed watching, unless something else came along that was more fun.
As far as viewing figures go, 3 stories get over 9 million, but most hover around the 7-8 million mark, with a couple dipping below 7. On average Series 4 does better than Series 3 at 8.05 million, reversing the downward trend of the last 3 years.