1. Cluster Analysis
What is cluster analysis?
Why use cluster analysis?
Nomenclature
Strengths and weaknesses
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5. What cluster analysis does
• Identifies subgroups in a population based on
some set of characteristics
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6. Some ~ Synonyms
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Cluster analysis
Unsupervised learning
Unsupervised classification
Automatic classification
Numerical taxonomy
Typological analysis
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7. Types of cluster analysis
• Connectivity models: Hierarchical clustering
• Centroid models: K-means algorithm
• Distribution models: Latent Class Models
• Density models
• Subspace models
• Graph-based models
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8. Heirarchical
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10. K Means
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11. Finite mixture model
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12. Density
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13. Model based cluster analysis
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Distributional
Latent class
Latent profile
Finite mixture model
Gaussian mixture model
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14. Hard vs. Fuzzy Clustering
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15. Strengths
• Empirical (Data driven)
• Handles complexity better than linear model
• Better suited for some theoretical tasks
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16. Limitations
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Subjective
Largely data-driven (empirical)
Computationally intensive
Variable selection
Model selection (how many clusters?)
Limited options for validation
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17. RESULTS
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SIMPLE STUNTING MODELS
These models only include binary
measures of stunting at each of 4
time points.
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20. The prevalence of stunting at each age.
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22. These make the most sense. They also suggest that stunting at 24 and 249 will tell most of the
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story.

23. These make sense, with group 3 as a “leftovers” group.
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24. Nonsensical group
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25. Nonsensical groups and/or trivial differences.
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26. Nonsensical groups and/or trivial differences.
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27. Nonsensical groups and/or trivial differences.
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28. Nonsensical groups and/or trivial differences.
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29. Dramatic improvement in model fit from the 2 to 3-class model. Minima for all three fit
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measures found in the 4-class model.

30. Dramatic improvement in model fit from the 2 to 3-class model. Best fit for the 4-class model.
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31. Best in the 2-class solution. Marginal differences between the 3 to 6 class solutions.
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32. Model >5 have classes with no modal assignments. 2 and 3 look good; 4 slightly less so.
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35. /bs
SIMPLE BODYSIZE MODELS
These models only include IOTF
measures of bodysize at each of 4
time points.
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45. Dramatic improvement in model fit from the 2 to 3-class model. Minima for all three fit
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measures found in the 6-class model.

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47. Not great overall. Best for 5 an 6.
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