Unit 8 · AI & the Impact of Computing · Lesson 8.8
Crowdsourcing and Citizen Science
One of the most detailed maps of the world was drawn by volunteers, one street at a time. Today: what crowds can build with computing — and the two weaknesses that come with them.
Big Idea 5 — Impact of ComputingCED 5.4 · callback to 5.10
Everything on this page is AP-TESTABLE unless it carries the CONTEXT — NOT ON THE AP EXAM label.
Before this lesson
No reading — this page is the reading. Retrieve 5.10: a self-selected sample isn’t representative, no matter how big it is.
Impact, as collaboration. The internet (Unit 6) lets millions contribute; Big Data (Unit 5) tells you what their contributions can and can’t show.
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The Hook
A map drawn by nobody in particular.
OpenStreetMap is built by volunteers adding roads, paths, and buildings. In many parts of the world it’s
more detailed than commercial maps — and during disasters, volunteers have mapped damaged areas within days
to help responders.
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The Idea
Crowdsourcing is getting input, information, or work from a large number of people via the
internet. Citizen science is scientific research done partly by everyday people — many of
them not scientists — who contribute data or effort using their own devices.
Examples: Wikipedia; volunteer maps; bird counts reported from backyards; online puzzle games where players
helped scientists work out protein structures; volunteers classifying galaxy photos.
What it enables: work at a scale no single organization could fund, data from places
researchers could never reach, and local knowledge outsiders don’t have.
Two built-in weaknesses. (1) Contributors are self-selected, so representation
is skewed — bird counts cluster where birdwatchers live, maps are richest where volunteers live (5.10
again). (2) Quality control has to be designed in — reviews, voting, cross-checks
— because anyone can contribute, including mistakes.
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Try It — Design the Quality Control
A citizen-science project asks volunteers whether each photo shows a particular bird. One common design: show
each photo to several volunteers and take the majority answer. How much does that help?
each volunteer is right:
volunteers per photo:
errors are:
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Vocabulary
crowdsourcing Impact
The practice of obtaining input or information from a large number of people via the internet.
citizen science Impact
Scientific research conducted in whole or in part by distributed individuals, many of whom may not be scientists, who contribute relevant data using their own computing devices.
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Check
Five questions. Ask who contributes — and who doesn’t.
0 of 5 answered
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Impact Check
Who maps whom?
If volunteers mostly live in wealthy cities, their neighborhoods get mapped in rich
detail and others stay blank. Then a delivery app or an emergency service relies on that map. Name one way a
crowdsourcing project could deliberately fill its gaps.
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Connections
Came from 5.10 — self-selected samples. Crowdsourced data inherits them.
Came from 6.10 — distributed computing: many computers. Crowdsourcing: many people.
Next in 8.9 — if millions contribute, who owns the result? Licenses and the law.