Continuity mistake: At the hospital, Dylan has a black eye and broken arm after Tom fell on him at his birthday party. A little later when Kate goes to the Shenk's house to tell them Mark has run away, Dylan shows no signs of the injuries he suffered. (01:04:45 - 01:18:25)
Continuity mistake: When everyone is walking to the new house, in the overhead shot you can see Tom and Kate walking with their arms around each others shoulders. Then when it cuts to a closeup, they are standing with their hands down by their sides. (00:20:55)
Continuity mistake: When the family runs across the football field to meet dad, ground angle shows the children running in different order both left to right and front to back than in the overhead angle. (01:29:45)
Continuity mistake: This takes place in the scene were Charlie Baker and Tom Baker are talking about Charlie missing his curfew: when Tom wakes Charlie up, notice how he is not covered up in his blanket, but in the next shot, you can see that it is over his legs, that would not be possible seeing as how Charlie was just then waking up.
Continuity mistake: When Charlie is doing his homework, he throws his pen on the book on his bed and looks at the picture of his girlfriend. He then picks his pen up from the book in his lap. (00:53:35)
Continuity mistake: As Steve Martin is ripping out pages in the phone book about babysitting services, if you look closely, you can see that it is the same page over and over again just shot at different angles.
Continuity mistake: When Hank is being attacked by the dog and the family is looking on and laughing, it cuts to Charlie laughing and he is holding a glass to take a drink, then it cuts back to Hank, and just a second later it cuts back to the family at the table and Charlie is sitting with his arm across his chair facing a completely different way, with nothing in his hands. There is no way he could have put down his glass and turned to lean back with his arm across the chair in that short of time. (00:40:20)
Continuity mistake: When the dad first gets into the bouncy castle to get his daughter, you notice him fall forward but then half a second later, he is standing up as if nothing happened.
Visible crew/equipment: When the kids are being punished by Tom for soaking Hank's underwear in meat, you can see a bit of the microphone from the overhead shot at the top of the screen. (DVD)
Revealing mistake: When Mark takes his pet frog to the other frog's grave, you can tell that the pet frog is a rubber toy, rather than a live frog. (00:18:55)
Other mistake: There are four days when Jake, Mark, Kim, Jessica and Mike are shown going to school in Chicago. All five wear the exact same clothes on the first three days, only on the fourth day are they dressed differently.
Other mistake: When Kate is telling the kids that their father is losing his job, Jake Baker is seen in the foreground, but in the next shot Sarah Baker is forward and Jake is behind.
Continuity mistake: When Beans, the frog, is just sitting on the pebbles and Mark is going, "Are you all right?", the the pebbles are bunched up on one end of the aquarium. But, in the shot where Mark goes back to his room AFTER Beans dies, the pebbles are bunched up on the other side.
Continuity mistake: At the kitchen table, Kate is throwing toast, and she throws one piece at Kim (the twin) who catchs it. Yet in the very next wideshot Kim is leaning on the table, with no toast in her hands, and Kate throws Kim another piece of toast again. (00:08:10)
Audio problem: When Steve Martin is talking to Bonnie Hunt on the phone and the kids are playing, a small dart lands between his feet. The sound the dart makes when it sticks to the floor is not accurate at all and deliberately sounds as if it comes from a object much heavier. (00:50:25)
Other mistake: When Jessica and Kim come down the stairs and Jessica is explaining what happened to Kim with Nigel and the dart, Kim looks at the camera.
Continuity mistake: When the teenage boy picks up the picture of him and his girlfriend, the position of the picture in his hand changes between shots.
Continuity mistake: After the scene where the kids get grounded, there is a scene of Mark laying in bed. He then rolls over in bed and stares at a picture of him and his mum. In front of the picture are his glasses, but in the very first overhead shot of Mark laying in bed, the glasses weren't in front of the picture. (01:01:00)
Continuity mistake: When Tom is being interviewed on TV, it cuts to Lorraine who says "At least we get to see him on TV" and she has both her legs bent up in front of her. In the following wideshot of the 8 kids and Kate on the bed, Lorraine only has one leg bent up in front of her. (00:27:55)
Continuity mistake: When the chandelier breaks and Tom falls whilst holding it, between shots the chandeliers lights go from being pretty much intact, to being totally smashed - and this is after the fall, so there is no reason for them to smash any more. The long yellow rope that attachs the chandelier to the ceiling changes the position it lays between the closeup of Tom landing (obviously not Steve Martin) and the following wideshot too. (00:24:25)
Answer: Because he needed a way to coach the team while also watching his kids.