Transcript A problem with the Long Tail

(Read the text in the notes panel at the bottom for narration)
A problem with the Long Tail
(Although an amazing number of
things are powerlaws, a lot of things
aren’t. How can you tell the
difference?)
A powerlaw
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90
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Sales ($)
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0
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Products
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Shown another way
Sales ($)
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Products
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WTF?
The Missing Market
Source: Morris Rosenthal
The problem
Examples of phenomena that
follow powerlaw distributions
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Species distribution among plants
Square footage of Alaskan Inuit homes
Forest fires, by size
Cities, by population
Death toll in wars
Earthquakes
Word use
Number of papers published by scientists
Examples of phenomena that
follow lognormal distributions
• Concentration of elements in the earth's
crust
• Latent periods of infectious diseases
• Survival times after cancer diagnosis
• Distribution of chemicals in the environment
(including pollution)
• Species distribution among moths and
diatoms
• Crystals in ice cream
• Length of words in spoken conversation
What’s the difference?
Powerlaws: created by “preferential
attachment” in scale-free networks.
Lognormal distributions: created by
"proportionate effects" (like growing by a
proportion of your weight).
Question
Assuming it all comes down to network
effects, how can you predict whether the
“natural shape” (free of bottlenecks and
other scarcity distortions) is a powerlaw or a
lognormal distribution?