Version 2, published October 12, 2026
A Ministry inspector at Hogwarts
Hogwarts: students and staff by house · Asked October 12, 2026 at 2:23 PM of 300 people
Synthetic simulation: these answers come from Jev's judgement of invented people, not from a survey.
What stands out
- Most were undecided, but more of them lean toward oppose: 24% lean support, 49% lean oppose.
- On the Ministry “Distrusts the Ministry” chose Oppose most: 68%, against 27% overall.
- On the Ministry “Trusts the Ministry” chose Yes most: 67%, against 44% overall.
- Cares most about “Getting ahead” chose Yes most: 61%, against 44% overall.
Hypotheses
Slytherins support a Ministry inspector more than Gryffindors.
H₀ Net lean among Slytherin is the same as net lean among Gryffindor.H₁ Net lean among Slytherin is higher than net lean among Gryffindor. (what you expect)Supported · Slytherin: net lean +18 · Gryffindor: net lean −23 · gap +41 points · 70 and 71 people
Each person's figure, in ten bands: how many people (weighted) fall in each. Triangles mark the means.
−1000+100Slytherin: mean +18Gryffindor: mean −23
Welch's t-test, one-sided: t = 6.21, df = 134, p < 0.001. H₀ rejected at the 5% level.
Gap, 95% confidence interval: +28 to +54 points. Effect size (Cohen's d): 1.04, large.
Group People Effective size Mean SD (points) 95% CI of the mean Slytherin 70 70 +18 34.8 +10 – +27 Gryffindor 71 71 −23 42.9 −33 – −12 SD is the spread of people's figures, in points (for a scale, points of its range). The effective size counts people by their weights.
Verdicts weigh size: supported takes a gap of 5 points or more the expected way; contradicted, 5 or more the other way; anything between is not supported.
With invented people, Jev's answers vary less than real people's, so p-values come out smaller than a real survey's would. How big a gap is matters more than its p-value.
Why this test
Each person's figure is an average of Jev's probabilities (or, for runs before October 2026, their single pick), so the test compares means rather than counts of 0 and 1.
Two groups: Welch's t-test, which does not assume the two groups vary equally; its degrees of freedom come from the data (Welch–Satterthwaite). Against everyone, the group is compared with everyone else.
One group on two questions: the same people answer both, so each person's difference is tested (a paired t-test), which removes what differs between people.
People count by their population weights, and each side's size is its effective size: (sum of weights)² ÷ sum of squared weights. "Higher" and "lower" are tested one-sided, "differs" two-sided, at the 5% level.
Groups are large, so this gives nearly the same p-value as a z-test; the t-test matters for small groups, such as two traits combined.
At a glance
Every question's answers, one bar each. Each question has its own answers and colours.
1Should the Ministry appoint an inspector to oversee teaching at Hogwarts?
2Do you think the Ministry should have a say in what Hogwarts teaches?
How the questions relate
Question by question
Pick two questions: each row is the people giving one answer to the first, split by their answers to the second. People count by their probabilities, so the margins are the run's shares.
Should the Ministry appoint an inspector to oversee teaching at Hogwarts? × Do you think the Ministry should have a say in what Hogwarts teaches?
| Share | Yes | No | |
|---|---|---|---|
| 18% | Support | 66% | 34% |
| 27% | Oppose | 33% | 67% |
| 56% | Undecided | 42% | 58% |
300 people answered both. Each row adds up to 100%.
Segments
People grouped by how they answered every question, into 4 segments of people who answer alike (k-means on their answer probabilities). Each shows its size, the trait values most over-represented in it, and its answers (top bar) beside everyone's (faded).
Segment 1 · 31% of people (94)
- On the Ministry “Not sure”: 100%, against 41% of everyone
- Cares most about “Magical creatures”: 16%, against 9% of everyone
- House “Ravenclaw”: 34%, against 23% of everyone
- Cares most about “Friends”: 31%, against 24% of everyone
1. Should the Ministry appoint an inspector to oversee teaching at Hogwarts?
2. Do you think the Ministry should have a say in what Hogwarts teaches?
Segment 2 · 29% of people (86)
- On the Ministry “Distrusts the Ministry”: 100%, against 29% of everyone
- House “Staff”: 13%, against 6% of everyone
- House “Gryffindor”: 35%, against 24% of everyone
- Cares most about “Studies and exams”: 35%, against 27% of everyone
1. Should the Ministry appoint an inspector to oversee teaching at Hogwarts?
2. Do you think the Ministry should have a say in what Hogwarts teaches?
Segment 3 · 23% of people (70)
- On the Ministry “Trusts the Ministry”: 100%, against 30% of everyone
- Cares most about “Getting ahead”: 36%, against 17% of everyone
- House “Slytherin”: 39%, against 23% of everyone
- Family “Pure-blood”: 44%, against 32% of everyone
1. Should the Ministry appoint an inspector to oversee teaching at Hogwarts?
2. Do you think the Ministry should have a say in what Hogwarts teaches?
Segment 4 · 17% of people (50)
- House “Slytherin”: 58%, against 23% of everyone
- Cares most about “Getting ahead”: 40%, against 17% of everyone
- On the Ministry “Not sure”: 60%, against 41% of everyone
- On the Ministry “Trusts the Ministry”: 40%, against 30% of everyone
1. Should the Ministry appoint an inspector to oversee teaching at Hogwarts?
2. Do you think the Ministry should have a say in what Hogwarts teaches?
The number of segments is the one, from 2 to 5, whose segments are furthest apart for their own spread (the Calinski–Harabasz score; higher is better: 2: 254, 3: 1063, 4: 1199, 5: 1171), leaving out any with a segment under 5% of people. The same run always gives the same segments.
Question 1 · Support or oppose
Should the Ministry appoint an inspector to oversee teaching at Hogwarts?
- Most were undecided, but more of them lean toward oppose: 24% lean support, 49% lean oppose.
- On the Ministry “Distrusts the Ministry” chose Oppose most: 68%, against 27% overall.
- On the Ministry “Trusts the Ministry” chose Support most: 51%, against 18% overall.
- On the Ministry “Not sure” chose Undecided most: 84%, against 56% overall.
Most likely answer: Support 20% · Oppose 28% · Undecided 52%
Of the undecided: 24% lean support, 49% lean oppose, 27% are torn.
Jev's average confidence 58%
± is the 95% sampling interval for these people (an effective 300 after weights): how far another draw of the same population could move a figure.
Model error is separate and wider: on 20 published questions, four answers in five landed within ±22 points of the real survey's share (±25 within groups).
How firm
Each person's lean from “Oppose” to “Support”: the gap between Jev's probabilities for the two, in ten bands. An even result can be two camps or a crowd in the middle; this shows which.
6% firmly toward “Support” and 21% firmly toward “Oppose” (a gap of 60 points or more); 43% within 20 points of even.
What drives the answers
How much of the variation in people's answers lines up with each trait. Traits overlap: pay travels with role, so both can rank high for the same reason.
With the other traits held constant
Each group's difference from its trait's largest group in net lean, in points, from one regression with every trait in at once, so a trait no longer gets credit for the traits that travel with it (pay with role). The dot is that effect with its 95% interval; the ring is the same difference one trait at a time, as the ranking above reads it. Where the two part, the trait's apparent effect came from others.
On the Ministry against Not sure
Role against Third to fifth year
Cares most about against Studies and exams
House against Gryffindor
Family against Half-blood
Together the traits account for 96% of the variation in people's answers (300 people).
House and On the Ministry together
Net lean in each combination of the two traits that drive answers most: support minus oppose, in points of average probability. Combinations of fewer than 30 people are greyed. Everyone: -9
| House \ On the Ministry | Trusts the Ministry | Not sure | Distrusts the Ministry |
|---|---|---|---|
| Gryffindor | +39 | -8 | -66 |
| Hufflepuff | +44 | -6 | -63 |
| Ravenclaw | +43 | -10 | -67 |
| Slytherin | +42 | -3 | -62 |
| Staff | – | -10 | -68 |
By house
Lean: support minus oppose, in points of average probability
By role
Lean: support minus oppose, in points of average probability
By family
Lean: support minus oppose, in points of average probability
By on the ministry
Lean: support minus oppose, in points of average probability
By cares most about
Lean: support minus oppose, in points of average probability
By segment
Lean: support minus oppose, in points of average probability
Who answered what
For each answer, the people who gave it most surely, as Jev read them. They show who answered, not why.
Support
Maisie Kettleburn
is a first or second year, still finding their way around the castle
Hufflepuff
cares most about their studies and their marks
comes from an old wizarding family
trusts the Ministry of Magic to tell the truth
75% sure
Imogen Pennifold
is a first or second year, still finding their way around the castle
Slytherin
cares most about getting ahead and knowing the right people
comes from an old wizarding family
trusts the Ministry of Magic to tell the truth
75% sure
Agnes Mumps
is a first or second year, still finding their way around the castle
Ravenclaw
cares most about their studies and their marks
comes from an old wizarding family
trusts the Ministry of Magic to tell the truth
72% sure
Oppose
Ottilie Fawley
teaches at the school
Staff
cares about Quidditch more than almost anything
comes from an old wizarding family
thinks the Ministry is hiding something
93% sure
Jasper Rookwood
teaches at the school
Staff
loves magical creatures
comes from a family with both wizarding and Muggle relatives
thinks the Ministry is hiding something
93% sure
Bartholomew Hartwell
teaches at the school
Staff
cares most about their studies and their marks
comes from an old wizarding family
thinks the Ministry is hiding something
85% sure
Undecided
Horace Fawley
is a first or second year, still finding their way around the castle
Gryffindor
cares most about their friends
comes from an old wizarding family
is not sure what to believe about the rumours
98% sure
Ned Gudgeon
is in their third to fifth year
Hufflepuff
cares about Quidditch more than almost anything
comes from a family with both wizarding and Muggle relatives
is not sure what to believe about the rumours
98% sure
Bartholomew Crumb
is a first or second year, still finding their way around the castle
Ravenclaw
cares most about their friends
comes from a Muggle family and found out about magic from their Hogwarts letter
is not sure what to believe about the rumours
98% sure
Question 2 · Yes or no
Do you think the Ministry should have a say in what Hogwarts teaches?
- On the Ministry “Trusts the Ministry” chose Yes most: 67%, against 44% overall.
- Cares most about “Getting ahead” chose Yes most: 61%, against 44% overall.
- On the Ministry “Distrusts the Ministry” chose No most: 72%, against 56% overall.
- House “Slytherin” chose Yes most: 56%, against 44% overall.
Most likely answer: Yes 37% · No 63%
Jev's average confidence 67%
± is the 95% sampling interval for these people (an effective 300 after weights): how far another draw of the same population could move a figure.
Model error is separate and wider: on 20 published questions, four answers in five landed within ±22 points of the real survey's share (±25 within groups).
How firm
Each person's lean from “No” to “Yes”: the gap between Jev's probabilities for the two, in ten bands. An even result can be two camps or a crowd in the middle; this shows which.
0% firmly toward “Yes” and 1% firmly toward “No” (a gap of 60 points or more); 19% within 20 points of even.
What drives the answers
How much of the variation in people's answers lines up with each trait. Traits overlap: pay travels with role, so both can rank high for the same reason.
With the other traits held constant
Each group's difference from its trait's largest group in net lean, in points, from one regression with every trait in at once, so a trait no longer gets credit for the traits that travel with it (pay with role). The dot is that effect with its 95% interval; the ring is the same difference one trait at a time, as the ranking above reads it. Where the two part, the trait's apparent effect came from others.
On the Ministry against Not sure
Cares most about against Studies and exams
House against Gryffindor
Role against Third to fifth year
Family against Half-blood
Together the traits account for 93% of the variation in people's answers (300 people).
Cares most about and On the Ministry together
Net lean in each combination of the two traits that drive answers most: support minus oppose, in points of average probability. Combinations of fewer than 30 people are greyed. Everyone: -12
| Cares most about \ On the Ministry | Trusts the Ministry | Not sure | Distrusts the Ministry |
|---|---|---|---|
| Quidditch | +28 | -34 | -53 |
| Studies and exams | +36 | -16 | -38 |
| Friends | +30 | -37 | -48 |
| Magical creatures | +32 | -36 | -50 |
| Getting ahead | +44 | +10 | -32 |
By house
Lean: support minus oppose, in points of average probability
By role
Lean: support minus oppose, in points of average probability
By family
Lean: support minus oppose, in points of average probability
By on the ministry
Lean: support minus oppose, in points of average probability
By cares most about
Lean: support minus oppose, in points of average probability
By segment
Lean: support minus oppose, in points of average probability
Who answered what
For each answer, the people who gave it most surely, as Jev read them. They show who answered, not why.
Yes
Horace Dimmock
is a sixth or seventh year, nearly grown and thinking about life after school
Slytherin
cares most about getting ahead and knowing the right people
comes from an old wizarding family
trusts the Ministry of Magic to tell the truth
76% sure
Cecily Dimmock
is a first or second year, still finding their way around the castle
Gryffindor
cares most about their friends
comes from an old wizarding family
trusts the Ministry of Magic to tell the truth
75% sure
Jasper Pennifold
is a sixth or seventh year, nearly grown and thinking about life after school
Ravenclaw
cares most about getting ahead and knowing the right people
comes from an old wizarding family
trusts the Ministry of Magic to tell the truth
75% sure
No
Ottilie Fawley
teaches at the school
Staff
cares about Quidditch more than almost anything
comes from an old wizarding family
thinks the Ministry is hiding something
81% sure
Imogen Wadcock
is a sixth or seventh year, nearly grown and thinking about life after school
Gryffindor
cares about Quidditch more than almost anything
comes from a family with both wizarding and Muggle relatives
thinks the Ministry is hiding something
80% sure
Elspeth Hartwell
is a sixth or seventh year, nearly grown and thinking about life after school
Gryffindor
cares about Quidditch more than almost anything
comes from a family with both wizarding and Muggle relatives
thinks the Ministry is hiding something
80% sure
How this was made
Who they are: Students and staff of Hogwarts School of Witchcraft and Wizardry, by house, in a year of uneasy rumours.
Background: A new school year has begun at Hogwarts. Talk in the common rooms is of rumours that a dark wizard thought gone for good may be back; the Ministry of Magic says this is nonsense and the Daily Prophet agrees. The Ministry has started to take a closer interest in how the school is run. The House Cup and Quidditch matter to most students more than politics; exams matter to fifth and seventh years. Students' families range from old wizarding families to Muggles who learned that magic exists the day the letter came.
What they were told before answering: The Ministry of Magic proposes to appoint an inspector who would sit in on lessons, approve what is taught and report on teachers.
Population built from the “Hogwarts: students and staff by house” template: 300 invented people, seed 60f9c957. Each person's traits come from the population's stated proportions; Jev (jev-1.13.0) judged how each would answer from those traits and from the context shown here, nothing else. Shares average each person's chance of each answer (Jev's full distribution), which lands closer to real surveys than counting each person's most likely answer; those counts are shown beside them.
Two kinds of error
Sampling: the ± beside each figure is a 95% interval for the people in this population, using their effective number after weights (Kish). It says how much the figure could move with another draw of the same population, nothing more. Rows too small to read (under 30 people, or an interval wider than ±15 points) are greyed out and left out of what stands out.
Model: how far real surveys land from Studio, measured on published questions with known results. Four answers in five landed within ±22 points of the real share on 20 questions that are not scales, and within ±23 on 24 scales (the average level within ±15 points of 100). This error is not chance and does not shrink with more people; it is why a contrast between groups is safer to read than a single percentage.
Synthetic simulation: these answers come from Jev's judgement of invented people, not from a survey.