Standard deviation measures the dispersion or variability of returns around the mean of a portfolio or security's historical performance. It is a widely used statistical metric in finance to assess risk, as it captures the degree to which returns can deviate from their expected value. A high standard deviation indicates higher risk, reflecting greater volatility in returns, while a low standard deviation suggests more stable performance.
Beta measures market risk relative to a benchmark, correlation measures the relationship between securities, and alpha represents excess return above a benchmark. However, standard deviation is the most common measure of total risk applicable to portfolios and individual securities.
* References:
* CSC Volume 2, Chapter 15: Introduction to the Portfolio Approach - Measuring Risk.
* CSC Volume 2, Chapter 16: The Portfolio Management Process - Risk Metrics.