Effective Number of Constituents
Install and import
npm install fintech-algorithmsimport { calculate } from "fintech-algorithms/market-breadth-and-internals/concentration-and-diffusion/effective-number-of-constituents";Signature
calculate(rows)Worked example
executed Captured by running this function on the input its own test provides. Real output of real code — but not asserted against a published figure.
Input
[
{
"security_id": "S01",
"weight": 0.17821782178217824,
"return": 0.065,
"sector": "Tech",
"ready": true
},
{
"security_id": "S02",
"weight": 0.13861386138613863,
"return": 0.041,
"sector": "Financials",
"ready": true
},
{
"security_id": "S03",
"weight": 0.10891089108910892,
"return": 0.028,
"sector": "Industrials",
"ready": true
}
]Showing 3 of 24 elements.
Call
calculate(rows)Returns
object with 4 fields: status, effective_n, actual_n, hhi
{
"status": "resolved",
"effective_n": 11.134761062719665,
"actual_n": 24,
"hhi": 0.0898088422703657
}Diagrams
How it works
This page states the contract — how to call it correctly. The article explains the concept: why it works, and where it breaks.
References
- Claim-to-source map
- Herfindahl-Hirschman Index — U.S. Department of Justice, Antitrust Division
- Diversity and Evenness: A Unifying Notation and Its Consequences — Mark O. Hill
- S&P Dow Jones Indices: Index Mathematics Methodology — S&P Dow Jones Indices