"That's how it is at Hogwarts. Copyin' lines! What good's that ter anyone? Yeh'll do sommat useful or yeh'll get out."
-- Rubeus Hagrid (PS15)
Detention is a form of punishment at Hogwarts in which the student has to carry out an unpleasant task after school hours. Punishments vary according to the nature of the crime. Some infractions result in points being deducted from the offender’s House. For other more serious offenses, detentions are handed out, or the staff member speaks to the Head of House (GF13). Teachers may assign detention tasks as they wish and some detentions have been actually dangerous. If a student refuses to accept the detention, they can be expelled. (PS15).
Prefects also have the authority to put students into detention. Ron threatened Seamus with detention once (OP11), and Malfoy did the same with Harry (OP10).
These detentions were handed out in the six years Harry attended Hogwarts.
- search the Forbidden Forest with Hagrid in the dead of night (PS15)
who: Harry, Hermione, Neville, Draco
why: wandering around the castle in the middle of the night
issued by: McGonagall
points taken: 20 from Slytherin, 150 from Gryffindor
result: school-wide bad feeling toward the three Gryffindors involved for improving Slytherin’s chances at the Cup; introducing Harry to the Forbidden Forest, the centaurs in general, and Firenze in particular; Harry learned the properties of unicorn blood - polish the silver in the trophy room without magic (CS7)
who: Ron
why: coming to Hogwarts in a flying Ford Anglia
issued by: McGonagall
points taken: none (school wasn’t technically in session yet)
result: Ron learned who Tom Riddle had been, having had a slug attack over his Special Award - help Lockhart answer fan mail (CS7)
who: Harry
why: coming to Hogwarts in a flying Ford Anglia
issued by: McGonagall
points taken: none (school wasn’t technically in session yet)
result: Harry was out of his dormitory late, and heard the basilisk for the first time - clean out the bedpans in the hospital wing without magic (PA9)
who: Ron
why: criticizing the way Snape taught when substituting for Lupin
issued by: Snape
points taken: none, technically, but he’d already taken 20 points over the course of the lesson up till then
result: Ron learned that Lupin didn’t spend his sick leave in the hospital wing - unnamed detention (PA13)
who: Marcus Flint, Malfoy, Crabbe, and Goyle
why: pretending to be Dementors to make Gryffindor lose a match
issued by: McGonagall
points taken: 50 from Slytherin
result: they didn’t try that again in a hurry - unnamed detention, together with loss of Hogsmeade privileges and denial of access to the Common Room passwords (PA14)
who: Neville
why: losing a list of the passwords to the Gryffindor common room, a list which Sirius Black obtained and used
issued by: McGonagall
points taken: none
result: Harry had to dodge Neville during the next Hogsmeade weekend in order to sneak out himself - disembowel a barrel full of horned toads (GF14)
who: Neville
why: melting his sixth cauldron in Potions
issued by: Snape
points taken: none
result: Hermione helped Neville afterward by teaching him a Scouring Charm; he later asked her to the Yule Ball, but she already had a date - pickle rats’ brains in the dungeons (GF18)
who: Harry, Ron
why: yelling at Snape
issued by: Snape
points taken: 50 points from Gryffindor
result: Harry had hoped to settle their quarrel during their joint detention, but a Daily Prophet article that same day poisoned the atmosphere - writing ‘I must not tell lies’ with Umbridge’s detention quill every night for the remainder of the week (OP12, OP13)
who: Harry
why: spoke the truth about Voldemort’s return and called Umbridge a liar in front of the entire class
issued by: Umbridge
points taken: none, technically; she’d already taken 10
result: Harry missed Gryffindor’s Keeper tryouts that Friday - writing ‘I must not tell lies’ with Umbridge’s detention quill every night for the remainder of the week (OP15)
who: Harry
why: talking back to Umbridge about Quirrell
issued by: Umbridge
points taken: none, technically; she’d already taken 5, and McGonagall, hearing about the incident, took another 5
result: Harry learned about murtlap from Hermione, although his right hand was still permanently scarred; Hermione was inspired to suggest what became the D.A. - writing lines (ordinary) (OP19)
who: Crabbe
why: hitting Harry in the back with a Bludger after the whistle had blown to end the match
issued by: Hooch (?)
points taken: none specified
result: taught the Slytherins that the system was a joke and the Gryffindors that it was unjust - a week’s worth of detention, unspecified – overruled by Umbridge, who changed it to a ban from Quidditch (OP19)
who: George, Harry; Umbridge included Fred
why: physically attacking Malfoy two on one after he insulted the Weasleys’ parents and Harry’s mother
issued by: Umbridge, who overruled McGonagall
points taken: none specified
result: Ginny took over as Seeker, the twins were no longer motivated to stay in school, Ron under pressure as Keeper - lines with Umbridge’s detention quill (OP25)
who: Lee Jordan
why: cheeked Umbridge about Educational Decree 26
issued by: Umbridge
points taken: none specified
result: Harry recommended murtlap to Lee, who recommended it to the twins, who used it to fix their Fever Fudge prototype - writing ‘I must not tell lies’ with Umbridge’s detention quill every night for the remainder of the week, loss of Hogsmeade privileges (OP26)
who: Harry
why: The Quibbler interview
issued by: Umbridge
points taken: 50 from Gryffindor
result: none from the punishment as such - whipping – but not accepted by offenders (OP29)
who: Fred and George
why: turning a corridor into a swamp
issued by: Umbridge
points taken: none mentioned
result: the twins cast a Summoning Charm for their Cleansweeps and left Hogwarts in a blaze of glory - sorting out rotten Flobberworms from good ones for use as Potion ingredients, without protective gloves (HBP9, HBP11)
who: Harry
why: cheek (“There’s no need to call me ‘sir’, Professor.”)
issued by: Snape
points taken: none mentioned
result: - unnamed detention on day of Hogsmeade visit (HBP12)
who: Draco
why: failing to turn in his Transfiguration homework twice in a row
issued by: McGonagall
points taken: none mentioned
result: Draco had an apparently cast-iron alibi for planting the opal necklace on Katie Bell - unnamed detention (HBP17)
who: Crabbe and Goyle
why: for slacking in Defense Against the Dark Arts
issued by: Snape
points taken: none mentioned
result: Draco complains that he wouldn’t be wandering around alone if Snape hadn’t put Crabbe and Goyle in detention, Snape claims that they need to do better in DADA classes if they are going to pass their O.W.L.s this time around, and it is important for them to “act” as though DADA is important - lines (ordinary): ‘I am a wizard, not a baboon brandishing a stick.‘ (HBP17)
who: Seamus Finnigan
why: not concentrating in Charms, to the point that he produced a hoselike jet of water rather than a fountain from his wand, knocking Professor Flitwick flat on his face in the process
issued by: Flitwick
points taken: none mentioned
result: - clearing out Filch’s old files recording punishments handed out – recopying any damaged records and filing them alphabetically without using magic – every Saturday until the end of term (HBP24)
who: Harry
why: cast Sectumsempra on Draco during an impromptu duel, then lied when questioned about where he learned the spell
issued by: Snape
points taken: none mentioned
result: Harry missed Gryffindor’s final match of the season, then kissed Ginny for the first time in the after-match celebration. Also, Snape had arranged matters so that Harry began with the records of theMarauders’ school years, which meant that Harry was constantly encountering mentions of them during his own detention. - unnamed double detention (HBP24)
who: James Potter and Sirius Black
why: cast an unnamed illegal hex upon Bertram Aubrey to swell his head to twice normal size
issued by: not named
points taken: none mentioned
result: Harry had to read the record of this detention and check it for damage as part of the contents of boxes 1012 – 1056 of Filch’s records during his own detention with Snape in his sixth year.
The threat of detention often leads to different student behavior. There are three different forms this threat works:
- The students receive a genuine threat after a certain behavior. For example, Filch threatened detention for students who left dirt on the floor (CS8, CS9, HBP19).
- The students think the staff member would surely put them in detention for behaving in a certain way and therefore do not behave like that. Snape did not have to really give his students detention, the perceived threat was enough (CS11, PA1, PA7). Because of this, Harry was set on completing Snape's essay during the summer holidays (PA1).
- The students manage to talk themselves out of detention. For example, when Harry and Ron managed to convince McGonagall they were visiting Hermione in stead of going to Myrtle's bathroom (CS16).
Professors McGonagall, Snape and Umbridge handed out most detentions.
Commentary
Etymology
This late Middle English word (in the sense 'withholding of what is claimed or due') stems from the Latin word detinere 'hold back' (Oxford Dictionary).