2015-04 ebay statistics
TRANSCRIPT
Welcome To
Director of Engineering
Search Science Recall & Spam
April 23, 2015
BRIAN JOHNSON
With more than 100 million active users globally, eBay is
the world's largest online marketplace, where practically
anyone can buy and sell practically anything. Founded in
1995, eBay connects a diverse and passionate community
of individual buyers and sellers, as well as small
businesses. Their collective impact on ecommerce is
staggering: In 2014, the total value of goods sold on eBay
was $82 billion -- more than $2,500 every second.
EBAY OVERVIEW
http://www.ebayinc.com/who
DATA DRIVEN DECISIONSMETRICS & TESTING
We Are Data
Fish Sticks
Demand Category
42%
Business & Industrial > Electrical & Test Equipment > Electrical Equipment & Tools >
Electrical Tools > Cable Pullers
10% Business & Industrial > Construction > Building Materials & Supplies > Electrical
9% Home & Garden > Tools > Other
7% Pet Supplies > Fish & Aquariums > Fish Pond Supplies
6% Business & Industrial > Light Equipment & Tools > Air Tools > Staplers
Fishing Sticker
Demand Category
41%
eBay Motors > Parts & Accessories > Car & Truck Parts > Decals/Emblems/License
Frames > Decals & Stickers > Graphics Decals
28% Home & Garden > Home Decor > Decals, Stickers & Vinyl Art
12% Sporting Goods > Fishing > Novelties & Gifts
11% Sporting Goods > Fishing > Fishing Equipment > Decals, Stickers & Patches
3% Collectibles > Transportation > Automobilia > Decals & Stickers
Fish Stickers
Demand Category
53% Home & Garden > Home Decor > Decals, Stickers & Vinyl Art
24% Crafts > Scrapbooking & Paper Crafts > Embellishments > Stickers
16%
eBay Motors > Parts & Accessories > Car & Truck Parts > Decals/Emblems/License
Frames > Decals & Stickers > Graphics Decals
3% Sporting Goods > Fishing > Novelties & Gifts
1% Sporting Goods > Fishing > Fishing Equipment > Decals, Stickers & Patches
Why?
www.wallpapertimes.com
$’s per year in
incremental revenue
Measuring Differences - Control vs. Treatment Tests
Test 1 Test 2
Control Treatment1 Control Treatment2
10.0 10.0 9.9 10.1
10.0 10.0 10.0 10.2
10.0 10.0 10.2 9.8
10.0 10.0 9.9 10.2
10.0 10.0 9.9 10.0
10.0 10.0 10.0 10.1
10.0 10.0 9.8 10.1
10.0 10.0 9.9 10.2
10.0 10.0 9.8 10.0
11.0 100.0 10.0 9.8
Mean 10.1 19.0 9.9 10.1
Median 10.0 10.0 9.9 10.1
StDev 0.3 27 0.11 0.14
T-Test 0.17 0.04
Experimental Variation By Day
Experimental Variation By Metric
METRICS
•What should we optimize
–Page Views
–Time on Site
–Click Through Rate
–Normalized Discounted Cumulative Gain
–Purchases per User per Session/Day/Week
–Revenue per User per Session/Day/Week
–Net Promoter Score
•How likely would you be to recommend …?
REVENUE
Every business focuses on and measures revenue.
Every business focuses on profit and loss.
And they should.
Be Careful What You Optimize For…
Sales
Revenue ($)
Time
FEATURES / FACTORS
Measuring Similarity - Words in Common
Jaccard Similarity
We see two sets A and B . There are three elements in their intersection and a total of eight elements that
appear in A or B or both. Thus, JaccardSimilarity(A, B) = 2/5.
I
Love
Statistics
Am
Learning
A B
Similar Item Titles
9 words overlap
4 words different
13 words total
Jaccard Similarity is 9/13 or 0.69
Measuring Similarity
http://blog.christianperone.com
Measuring Similarity
http://blog.christianperone.com
Compound/Decompound Expansions
Add “acidwash” > “acid wash”
Before After
Context Matters
Uncontexted expansions: cowboys cowboy
cowboys hats ≠ cowboy hats Plastic toy cowboys = plastic toy cowboy
Features: Mutual Information
• Rationale: The goal of this metric is determine if the co-occurrence of
the candidates in the description is significantly more than the
random chance of them co-occurring.
Features: Neighborhood Similarity
• Rationale: Two synonym candidates A and B, will tend to
have similar neighbors (viz keywords) surrounding them.
Intersection ( Neighbours(A) , Neighbours(b) )
Min (Neighbours(a), Neighbours(b))
Neighborhood similarity =
Features: KL divergence
• Rationale: Two synonym candidates will have similar
price and category distributions of their inventory.