How do you take millions of users with 100’s transactions each, amongst 10k’s of products and group the users together in meaningful segments?

Data Science Interview Questions › Category: Data Science › How do you take millions of users with 100’s transactions each, amongst 10k’s of products and group the users together in meaningful segments?
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MockInterview Staff asked 7 years ago
1 Answers
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MockInterview Staff answered 7 years ago
  1. Some exploratory data analysis (get a first insight)
  • Transactions by date
  • Count of customers Vs number of items bought
  • Total items Vs total basket per customer
  • Total items Vs total basket per area
  1. Create new features (per customer):

Counts:

  • Total baskets (unique days)
  • Total items
  • Total spent
  • Unique product id

Distributions:

  • Items per basket
  • Spent per basket
  • Product id per basket
  • Duration between visits
  • Product preferences: proportion of items per product cat per basket
  1. Too many features, dimension-reduction? PCA?
  2. Clustering:
  • PCA
  1. Interpreting model fit
  • View the clustering by principal component axis pairs PC1 Vs PC2, PC2 Vs PC1.
  • Interpret each principal component regarding the linear combination it’s obtained from; example: PC1=spendy axis (proportion of baskets containing spendy items, raw counts of items and visits)

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