Newsround's Lizo says: I've changed the scoring system I use for Doctor Who to bring it into line with the other reviews on the Newsround site. The scale basically works like this.
0 out of 5 - terrible!
1 out of 5 - pretty bad. I wouldn't give either of these marks to any episode I've seen so far.
2 out of 5 - not very good, and disappointing by Who standards. The only story I'd give 2 to would be last year's Fear Her.
3 out of 5 - an ok episode, some good bits and some not so good bits. I'd give Daleks in Manhattan a 3.
4 out of 5 - pretty good, even by Who standards a pretty special story. I'd give last year's Love and Monsters a 4.
5 out of 5 - outstanding, exceptional, a brilliant episode. I'd give last year's last episode Doomsday a 5 out of 5. I can't remember the last time a piece of TV had me in floods of tears on the sofa for the last 15 minutes.
One more change - once you've seen each week's episode, you can let us know what you think using the form at the bottom of my review, and each week we'll publish a selection of your comments.