Data Dive · Rung 1 · What's There · 1.5

Two ways a donut fails

Slices too close to rank, and one slice that swallows the rest.

Runs in 20 minutes · everything you need is on this page · no network, no accounts, nothing for the students to open

1.5→ next · ← back · esc leaves0 / 4

Too close to call

What Los Angeles is asked to do

What Los Angeles is asked to do, 2022311 requests by type - three of these are too close to rank by eyerequests loggedrequest typerequests logged308,443616,8860616,886Bulky Items323,720Graffiti Remov105,413Metal/Househol100,022Illegal Dumpin60,247Homeless Encam38,254Electronic Was27,828Dead Animal Re18,505Multiple Stree

311 requests by type, 2022

46.5%
bulky items
7.9 / 7.5 / 4.5%
three slices nobody can rank by eye
Do this firstPut the slices in order smallest to largest WITHOUT reading the numbers. Then check. Count how many pairs the room got wrong.
1.5 · Two ways a donut fails→ next · ← back · esc leaves1 / 4

Swallowed

How deep the earthquakes are

Southern California earthquakes by depth, 202490.3% are shallow - and the deep band rounds to 0.0%earthquakes recordeddepth bandearthquakes recorded1,1322,26502,265shallow243intermediate0deep

Southern California, 2024

90.3%
shallow
0.0%
deep -- and they exist

Deep earthquakes happened. They are in the file. The donut draws them as nothing.

1.5 · Two ways a donut fails→ next · ← back · esc leaves2 / 4

The point

Angle is the hardest thing for an eye to judge

A donut is good at one job: showing that one thing is most of the whole. It is bad at everything else, including the thing people most often use it for.

The three questions
  1. Put the slices in order without reading the numbers. Which pairs did you get wrong?
  2. What percentage is the biggest slice?
  3. Bulky items is 46.5% of everything the city is asked to do. Is that what you would have guessed?
1.5 · Two ways a donut fails→ next · ← back · esc leaves3 / 4

After the dive

The shapes on this page, in the library’s own words

the donut

Slices add up to the whole thing. Good for parts of one total, bad for ranking.

What it leaves outSlices close to the same size cannot be told apart, and one large slice flattens every other into a sliver you cannot read.
the bar

Bar length is the value, so it only means anything measured from zero. Start the axis anywhere else and the lengths stop matching the numbers.

What it leaves outOrder is a choice. Sorted by size it is a ranking; sorted by name it is a lookup; and the same bars say different things in each.

library · ladder · dives · the pool · this dive’s worksheet

1.5→ next · ← back · esc leaves4 / 4