Title: Discussion
Course: Advanced Data Science: A Graduate Course > Section: Module 6: Unsupervised learning: clustering and PCA

Post an initial argument by mid-week on this prompt: why is “the elbow” a weak standalone argument for the number of clusters? Draw on the readings and your practice to explain what the elbow method actually measures, why it is subjective and often ambiguous, and what evidence you would add to make a count credible. Then reply substantively to at least two peers, either strengthening or challenging their proposed evidence. The instructor responds within each thread to push the reasoning further.