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Reading Guide to the Aggregation Section

This page is a navigation map for the Aggregation section.

The section can be read in different ways depending on what you are looking for. Some readers may want a short conceptual overview. Others may want the data first, or the main theoretical mechanism, or the technical appendices.

Start here​

If you are new to this section, begin with these pages:

Reading routes​

Route A. New reader in 20 minutes​

A short path for broad audiences.

Route B. Economist route​

A path for readers interested in aggregate volatility, diversification, trade concentration, and firm heterogeneity.

Route C. Empirics-first route​

A path for readers who want the data, empirical patterns, and measured components first.

Route D. Full theory route​

A path for readers who want the conceptual and mathematical backbone.

Section clusters​

1. Motivation and orientation​

2. Literature and economic motivation​

3. Data and empirical foundations​

4. Core framework​

5. Diversification, population size, and covariance structure​

6. Extensions and realism checks​

7. Appendices and technical support​

If you want only the main line​

If you want the shortest route that still captures the main argument, read these pages in order:

  1. Introduction to Aggregate Volatility
  2. Data and Methods
  3. Firm Level Fluctuations
  4. Mathematical Framework: Aggregate Volatility in Log Scale
  5. Firms are not Sectors
  6. Reviewing the Diversification Issues
  7. Understanding Comovements and Variance in Large Numbers
  8. Origin of Departure from LLN
  9. Conclusion on Volatility Aggregation

If you want the technical backup​

These pages provide supporting derivations, robustness arguments, and simulation details: