New York's trash shows where the city went in 2020, one district at a time

SECTION 01The scale nobody reads

Every truck the Department of Sanitation sends out comes back to a scale. The city adds up what it weighed, district by district, and publishes it every month.

The record starts in January 1990. It covers all 59 community districts, split by what went in which bin: trash, paper, bottles and cans, and compost.[1] We read every row of it: 25,296 district-months, and more than 121 million tons since 1992, when every district first appears in every month.

The city collects from homes, public schools and institutions. Businesses hire private carters, so an office tower or a restaurant never touches this scale.[2] What the file weighs is where people live.

Nobody runs a business on this file. It is there to plan truck routes and pay landfills. But a scale that has weighed the same doorsteps every month for thirty-six years is also a census that never stops. In 2020 it said something the official count took almost two years to say.

SECTION 02What an ordinary year looks like

Before believing anything about 2020, we measured how much a district's tonnage moves when nothing in particular is happening.

For every district and every year from 2011 to 2019, we compared April to December with the same nine months a year earlier. That is 530 ordinary district-years. The typical one moved +0.36%, nineteen in twenty moved less than 5.06% either way, and the most extreme of all ran from -10.14% to +11.22%.

One district-year is not in that count. In January 2018, Queens district 7 stepped up by about 2,100 tons a month overnight and stayed there for good, with no neighbouring district dropping by the same amount. People do not start throwing away that much more in one night. A change like that is in how the tons were counted or collected, and finding those before reading anything else is half the job.

An ordinary district moves a few percent a year. The wildest one in nine years moved about 11 percent.

SECTION 032020, all 59 districts

Then the same comparison for April to December 2020 against 2019, every district at once.

6 districts fell further than any district had in nine ordinary years, and 14 rose higher than any had. Measured against its own history instead of everyone's, 47 of the 59 districts left their own 2011 to 2019 range.

THE CITY, a New York newsroom, reported the outline of this in 2020 from the first months of data: every district south of Harlem down, the other four boroughs up.[3] What had not been done was to put it against what an ordinary year looks like, which is what turns "down" into "further down than anything in nine years", or to come back and see what happened next.

The direction is a map.

Midtown and Flatiron threw away 20.69% less. Wall Street and Tribeca 18.07% less. Greenwich Village and SoHo 14.33%, the Upper East Side 13.62%, the Upper West Side 11.53%. Of the 12 districts that threw away less at all, eight are Manhattan below Harlem.

Everywhere else went the other way. Throgs Neck and Co-op City rose 14.86%, Crown Heights and Prospect Heights 14.18%, Wakefield and Williamsbridge 14.11%. 47 of 59 districts threw away more.

SECTION 04The month it happened

A single month is a noisy thing to read, because one month can hold more collection days than the next. So instead of raw tons, take the seven Manhattan districts' share of everything the city collected that month. Anything that hits every district alike, the calendar, a snowstorm, a holiday, cancels out of a share.

In February 2020 those seven districts made 10.69% of the city's tonnage. In April, 8.08%. Against April 2019 that is a fall of 2.08 points. From 2011 to 2019, the same month-against-last-year comparison never moved more than 0.72 points.

The lowest month since 1992, the first year every district appears in every month, is June 2020, at 7.86%. The scale saw it the month it happened.

The Census Bureau's estimate for Manhattan came out on March 24, 2022: 117,375 fewer people between April 2020 and July 2021, 6.9%, the largest percentage loss of any county in the country with 20,000 people or more.[4] That is twenty-three months after the trucks came back light.

SECTION 05Five tons for every one

If people had only moved from Manhattan to Queens, the tons would have moved with them, and the two numbers would roughly match. They do not.

From April to December 2020, the seven Manhattan districts collected 37,395 fewer tons than a year before. The other 52 districts collected 187,296 more. That is 5.0 tons gained for every ton lost, and the city as a whole collected 5.35% more. Its best ordinary year from 2011 to 2019 was +3.45%.

The extra came from somewhere else. The city's scale weighs homes, and in 2020 the lunch that used to be eaten at a desk, the coffee cup, the takeout box and the office kitchen's recycling all came home.

The scale never saw the trash leave the offices and restaurants, because private carters haul those. It only saw it arrive at home, five tons for every one that left Manhattan's apartments.

The trash did not move out of Manhattan. It went home.

SECTION 06What was in the bins

The streams say what kind of year it was. April to December 2020 against 2019, by borough:

Bottles, cans and plastic rose 19.31% across the city, and by more than a quarter in Queens and Staten Island. Even Manhattan, which threw away less trash, recycled 3.69% more of them.

Paper is the strange one. A year of everything delivered in a cardboard box looked set to bury the paper trucks. Across the city, paper rose 3.82%, inside its ordinary range, and in Manhattan it fell 11.68%, further than the trash. The boxes went where the people went.

SECTION 07Five years later

Here is the Manhattan core's share of the city's tonnage over the whole record, one point a year.

For twenty-eight years the share drifted between 9.58% and 11.74%, and never moved more than 0.85 points in a year. In 2020 it fell 1.47 points. By 2025 it was back to 9.69%, about 57% of the way home.

Which part came back is its own finding. Midtown is within 1.38% of 2019. The Upper West Side is still 10.67% lower and the Upper East Side 9.37% lower, where the rest of the city is 0.83% lower. Midtown and Flatiron, Chelsea and Clinton, and Wall Street and Tribeca came closest to 2019. The two uptown neighbourhoods of apartments either side of Central Park are still about a tenth lighter than they were.

SECTION 08What the trash does not know

We tried the obvious next idea and it failed. If the scale knows where people are, maybe it knows how the economy is doing, before the jobs report does.

It does not. Across 300 months from 1995 to 2019, we lined up the yearly change in the city's tonnage with the yearly change in New York City jobs,[5] shifted forward and back by up to a year. The strongest relationship at any shift was 0.18, which is close to nothing, and its sign flips depending on the shift.

So the scale is not a crystal ball. It measures one thing very well, which is where people spend their days, and nothing else very well at all. Knowing which question a source can answer is most of the skill.

SECTION 09The point

None of this file was collected to measure a pandemic. It was collected to route trucks. It still answered a question about where New Yorkers went, month by month and street by street, because it was weighed every month whether anyone looked or not.

Every business has files like this. The void log at the register. The refunds. The time clock. The delivery manifests. The calls that went to voicemail. Nobody counts them as data, because they were made to run the place, not to understand it. They are weighed every day anyway.

Reading them takes a data team: 25,296 rows, 530 ordinary cases measured before the interesting one, a district that changed how it counted caught and set aside, and a test that failed and got said out loud. That is a week nobody running a business has spare.

The scale saw it first. It just had nobody reading it.