New Haven garbage collection: 1983-1988

source: practical work project by Evelyn Crowley (Statistics Department, 1989), using data supplied by Mr. Richard Wolf, Solid Waste Manager at the Department of Public Works, New Haven.

The data were analyzed in order to predict how much garbage would have been collected if recycling had not been introduced in 1990. Apparently, the aim was to convince the State that New Haven was in compliance with the State recycling law: post-1990 garbage levels were to be compared with predictions based on pre-recycling data, demonstrating reductions attributable to recycling.

For each of the five weekdays, garbage was collected on each of nine routes. The recorded data (column 2) give total amount collected, rounded down to the nearest ton, for 311 weeks (column 1). Week 1 ran from Monday 3 January, 1983 through to the Friday of the same week; week 311 ran from Monday 12 December, 1988 through to the Friday of the same week. Weeks for which totals were missing are indicated by a period. A few weeks (weeks 148,...) for which almost complete data were available have been completed by interpolation between adjacent weeks for a missing route.

Column 3 lists holidays that affected the collection of garbage; column 4 lists the date on which the holiday fell. (Note: this is not always the date one might expect.) The holidays were:

new = New Year 
king = Martin Luther King day 
linc = Lincoln's birthday 
wash = Washington's birthday 
gfri = Good Friday 
mem = Memorial day 
jul = Fourth of July 
lab = Labor day 
col = Columbus day 
vet = Veteran's day 
thank = Thanksgiving 
xmas = Christmas
SNOW = day on which large snowfall noted (not a holiday)
If a holiday fell on a weekday, the collection schedule was usually modified, with a special collection on the Saturday to make up for the missed day, and all collections after the holiday made a day later than usual. For example, a Good Friday fell in week 13. Garbage was collected as usual on the Monday through Thursday; Friday's collection was moved to the next day. Another example: in week 8, the collections that should have been made on the Monday (Washington's birthday) were actualy made on the Tuesday; the usual Tuesday collections were made on Wednesday; the usual Wednesday collections were made on Thursday; the usual Thursday collections were made on Friday; and the usual Friday collections were made on the extra Saturday. For that week, eight days worth of garbage were collected from each route; the following week, only six days worth were collected.

The snowfall on the Friday of week 62 resulted in an incomplete collection which was continued on the Saturday.

In 1986, weekly totals were recorded only for the first three months. Monthly totals (rounded down to nearest ton) were recorded for all months:

Jan		3063
Feb		2325
Mar		2448
Apr		3157
May		3291
Jun		2876
Jul		3099
Aug		3035
Sep		3317
Oct		2879
Nov		2959
Dec		3248
Comparison with weekly data for the first three months of 1986 shows that the January 3063 tons equals the sum of totals for the collections from monday 30 December, 1985 through Friday 31 January, 1986. The March 2448 tons is the sum of collections from Monday 3 March through Friday 28 March. (Only daily totals, not the usualk brealkdown by routes, are given for March 26, 27, 28. There should have been no collection on the last day -- Good Friday -- but 72 tons were recorded.) One week was missing from the February totals; direct comparison with the 2325 tons is not possible. The data sheet indicates that the monthly totals were extracted from some form of computer records.

The data sheets for the second half of 1987 and the last few months of 1988 are less detailed than for the earlier years. They give weekly totals, with a few missing weeks estimated by an unspecified method.