Compare Unsupervised Clustering Methods
Quick Overview
This question evaluates understanding of unsupervised clustering algorithms and related competencies such as algorithmic objectives, assumptions about cluster shape and scale, hyperparameter considerations, computational scalability, evaluation without labels, and preprocessing of high-dimensional or sparse features within the Machine Learning domain. It is commonly asked to assess an engineer's ability to compare centroid-based, hierarchical, density-based, Gaussian mixture, and spectral approaches, reason about trade-offs and common failure modes, and relate algorithm choice to data characteristics and resource constraints. The level of abstraction spans both conceptual understanding of model objectives and assumptions and practical application concerns such as complexity, hyperparameter selection, and preprocessing strategies.
Explain several unsupervised clustering approaches and when you would use each one. At a minimum, compare centroid-based clustering, hierarchical clustering, density-based clustering, Gaussian mixture models, and spectral clustering.
For each method, discuss:
- the core objective or intuition,
- assumptions about cluster shape and scale,
- important hyperparameters and how to choose them,
- computational complexity and scalability,
- strengths and common failure modes,
- how to evaluate clustering quality when labels are unavailable,
- how you would preprocess high-dimensional embeddings or sparse features before clustering.