Continuity mistake: After Dawson and Eve check his locker to see if the PSAT test was returned, they then start talking in the hallway next to his locker. Just as Eve says "Tell me who you think it is", there is a shot of her from the rear as she turns around to face Dawson with her arms crossed in front of her, and down by her sides. The next shot of Eve is from the front, as she says "Whoever you were just thinking of"; and suddenly her arms are at an angle away from her sides with her hands on her hips. Then the next shot of Eve is from the rear, and again her arms are straight and back down close to her sides as she says "It is". Then the next shot of Eve, again from the front shows her arms back out at an angle again with her hands on her hips as she says "Simple and obvious". There was no time for her to have moved her arms and hands during this scene, the transition was too fast. Apparently the shots of Eve from the front, and from the rear during this scene were filmed at two different times.
Continuity mistake: When Andie is doing sit-ups in the morning and practicing for the PSAT, she is listening to the news on TV. The news anchor mentions the author of the popular book "Cracking the PSAT". She says 'PSAT' not 'SAT'. But Andie immediately says something like "Way ahead of you", and holds up her copy of the book. On the cover, it says "Cracking the SAT", not 'PSAT'.
Continuity mistake: Right after Pacey leaves Dawson's bedroom at the beginning of the episode, Dawson looks out his side window to see Pacey leave and suddenly notices flashlights in the dark house next door. It's clear that Dawson is looking out the side window on the right of his bed, as he is directly facing Jen's house. There is also a side window to the left of his bed which also faces the same direction. But in a later episode (Guess Who's Coming to Dinner); they show a wide shot of that side of Dawson's house. There are two windows on that side of his house facing Jen's house, but they are on each side of a chimney and the two windows make up the complete upstairs (looks more like two rooms). But whenever we see Dawson's bedroom, it's much smaller and does not take up the complete upstairs space of the house. In fact, there is a clear upstairs stair landing that his bedroom is off of, and this landing looks out over a large open space with the dining room, living room, etc. So there is no way that Dawson's room with both side windows could possibly take up the entire sideways width of the upstairs as is shown from the outside. There is also no fireplace and chimney that runs the entire height of the house on that side of the house, and which would in theory be located right where Dawson's bed is between his two side windows. Obviously the real house exteriors differ considerably from the inside sets.
Continuity mistake: When Jen walks into the Video Store, she is wearing a black top, red skirt and a black leather jacket that is completely open and unbuttoned. As she talks to Dawson, who is behind the counter, she says, "I'm working on a project with Pacey in a 'human growth and development' thing - is he here?" She is standing up, but leaning slightly forward against the counter and her coat is still widely open. But the next shot of Jen, as she says, "But he told me that he was working today," the black leather jacket is suddenly closed together as if buttoned, and she is leaning foward more on the counter. Then, after Dawson walks over to the movie rack and Jen follows him, her jacket is again hanging completely open and unbuttoned.
Continuity mistake: When Jack and Andie are using the computer with Ben's Instant Message on the screen, there is a close-up of the computer screen as they wait for Ben's photo to download. Just to the right of the photo is the entire IM, which shows all 3 lines of dialogue between Ben and Jack. The last line says, "So. What do you think?" But after the photo is finished, there is a sudden 'beep' from the computer signalling another incoming IM message, which Jack then reads out loud as if it is a new message. But what he reads is, "So. What do you think?", the exact same line that was already in the IM box before the photo finished downloading. The implication is that he is reading a message that just came in, yet that line of dialogue from Ben was already present in the IM box previously.
Continuity mistake: When Pacey is nursing his black eye with a raw steak, Joey comes into Doug's apartment to talk to Pacey. Just when Pacey says, "Looking out for ya," there is a frontal shot of Joey. Her hair is bunched up considerably in the back, near her right ear. As Pacey says, "To look after said girl," the next shot of Joey shows the bunched up hair in the back suddenly gone, and her hair is smooth.
Continuity mistake: At the end of the episode, Joey and Pacey are repainting over the ruined mural with light blue paint. Joey starts to paint a small section of the wall with her roller. Dawson then comes out of a room, and glances down the hallway to see them both painting. But Joey's patch of light blue paint at this point is suddenly much larger. It doesn't seem realistic that Joey would have been able to paint that much more of the wall, in the short amount of time elapsed.
Continuity mistake: When Pacey is driving Joey back from Boston in the morning, they start talking about what happened. Every shot of Pacey or Joey from either side shows a heavily wooded forest (mostly pine trees it looks like) in the background. But when Pacey abruptly veers off the road to the right and parks; suddenly the landscape on Joey's side is barren with a huge lake, and no forest or trees except a few they just passed on the curve. The pine tree footage was probably added in to make Wilmington, NC look more like Capeside, Mass.
Continuity mistake: When Andie and Jack are discussing Ethan's visit while sitting outside eating breakfast, Andie pours milk over her cereal, puts down the milk, takes her spoon in her right hand, then into her left hand. The immediate next camera angle shows Andie holding the milk again, closing it and putting it down, again. (00:06:22)
Continuity mistake: When Aunt Gwen is talking to Dawson and Joey in the store, just after she says, "General all around cuddliness between the two of you"; Joey is facing her and Dawson is turned the other way, with his back to her. But the next shot of Dawson is a close-up, and he is suddenly facing Aunt Gwen as he says, "OK, I'll tell you the long soap opera short". The transition was too fast to be realistic, or to have given Dawson enough time to turn completely around to face Aunt Gwen.
Continuity mistake: This episode shows a full day's events repeatedly in 4 separate segments, and it appears they reused the same scenes and dialogues. But there are noticable differences between Act 3 and Act 4. At the end of Act 3, when Dawson confronts Joey and Pacey about their relationship; he says to William and Andie, "Better yet, ask Joey. Ask her how long [she's] been lying to me and to you." During this same scene in Act 4, Dawsons varies it slightly: "Better yet, Ask Joey. Ask her how long [the two of them] have been lying to you and to me." He also switches 'you and me' interchangeably. Act 3, Dawson further says, "Go ahead ask them, because I can't [stand to look at them]." But in Act 4, he changes it to "Go ahead ask them, because I can't [even stand to look at them anymore]." The way these two scenes were shot varies also. During Act 3, when Dawson is finished talking he storms back into his house, and makes it inside the inner front door alone. But in Act 4, Dawson starts running back into his house with Joey following close behind him, so that she is in the frame when he reaches the inner front door.
Continuity mistake: When Joey meets Dawson before The Anti-Prom, he loans her his mother's diamond earrings. Just as Bessie says "Put them on, and then I'll get one more picture"; there is a close-up of Joey as she puts an earring in her right ear. It appears that she has just started putting the earrings on; but then she turns to face forward for the photo with Dawson, and you can see both earrings already on her ears. Joey started putting the right earring in just after Dawson told her to put the earrings on, so how did the left ear get done?
Continuity mistake: At the very end of the episode, when Joey and Pacey are sailing out into the sunset the sky keeps changing between shots. When they are first setting off, it's earlier in the day with bright sun and a cloudless sky. The sun appears at a high angle. The next shot, as they sail further the sky is suddenly full of clouds and it's almost sunset, with the sun lower in the sky. The final shot after that, the sky is still cloudy and in sunset hues as the sun appears just over the horizon about to set. Obviously these shots were taken at different times of the day, although they appear to be right after each other in the show.
Answer: It's only explained once in the series. Jack says to Andie "I tried to start kindergarten without you", meaning Andie was smart enough to start school early.