A research page is frozen the day it is published.
Every other page on this site recounts its figures each time the site is published. A research page does not. Its numbers are pulled once, written to a file, and served unchanged until someone republishes the page on purpose. 23 of the 35 figures this site tracks against current data sit on the four studies below. Each is stored with the query that produced it, the date it was published, and how far it may move before it counts as drift.
A citation is the reason. A reader who quotes a number in a filing, an article or a brief needs it to say the same thing when someone looks next month. A figure that is recounted on every publish moves under the reader, and a figure that moves cannot be quoted, however recent it is. So the two kinds of page here do opposite jobs on purpose: a guide and the borough pages are as current as the last publish, and a study holds still.
See what is open on one building.
NYC heat violations spike every October.
Heat season starts October 1, and violations turn with it rather than after it. September has 6,628 heat and hot water violations against October's 10,419, and January runs 4.4 times September's volume. The page has the month-by-month shape, the same September-to-October comparison for every year separately, and a control group of violation categories with no seasonal rule, which do not move. 4 of its figures are in the drift register.
Heat certifications mostly arrive on time. Half never arrive.
New York City gives a landlord 24 hours to restore heat, and the notice sets a later date to certify the repair, a median of 13 days out. HPD has recorded 149,537 Class C heat and hot water violations since August 7, 2023. 73,049 of them have a certification on file, which is 48.9%, and 93.1% of those met that date. The gap is the half with none: 19,631 have stood open more than a year with nothing filed. The page measures it year by year and shows the certification rate has not drifted with volume. 7 of its figures are in the drift register.
A Class C violation not certified in 90 days almost never is.
Every Class C violation HPD recorded from August 27, 2023 through September 24, 2024 has had two years for a certification to arrive. 47.0% have one, nearly all filed in the first 90 days, and of those still uncertified on day 90 only 1.9% were certified later. The page follows every quarter separately and splits the uncertified by what HPD's own status says now. 5 of its figures are in the drift register.
Where a Class C violation is open, what else is.
On September 24, 2026, 35,864 properties had an open Class C violation. The page counts how many of them also had a pending OATH hearing on a DOB summons, a pending housing court case, active DOB violations or a vacate order in effect, each the way the building pages show it, and how many have rent-stabilized apartments on their registration. Every count was taken twice and frozen where the two agreed. 7 of its figures are in the drift register.
What freezing costs, and what happens to a stale figure
A frozen number goes out of date. The data it came from keeps moving, so we measure the gap rather than hide it. Every figure on every study is entered in a register kept in this site's own source, with the query that produced it and a threshold for how far it may move before the gap matters. Each week a job re-runs all 35 entries in that register against the data as it stands that day and reports what has moved.
The job only reports. It does not rewrite the page or the register, because a published figure that has moved is a decision for a person: republish the study with a new date, or leave it and say when it was measured. Each study states its own date on the page, and the first of these figures was published August 30, 2026. The two heat studies cover inspections from August 7, 2023 through September 24, 2026, and the certification study covers our copy through September 24, 2026.
What a study here is not
Every study is an aggregate: of HPD violations, counted by violation, or of properties, counted by tax lot. No building, owner, tenant or address is named on any of them, and none is named here. A median is the middle case: half the certified violations in that group cleared faster and half slower. Every percentage is stated with the group it is a percentage of, because the share ever certified and the share still open past a year are different questions with different denominators.
HPD's own file lags the inspector by days to weeks, so the newest cases are under-counted in any measurement taken from it, these included. No study claims to explain why a number is what it is. Each one sets HPD's data against a standard the city set, and stops there. Ask for the query behind any figure at press@violationscout.com.
Where this sits
A status name on its own is decoded in the status glossary. How long things take and how often they happen is in the guides, recounted every publish. Current counts by borough and category are on the borough pages, and citywide on the citywide page. How HPD, DOB and OATH/ECB divide the work is on the agencies page. What we hold and how we count it is in the method.
No building or owner is named on this page. Source: NYC Open Data, our own copy, pulled September 26, 2026. Citywide, ViolationScout.
Every figure above comes from a query we can share. Cite the page with the date at its top. Ask and we will send the query.
Ask for the query