# Historical Returns The Historical Return model uses historical data from the selected time series returns to estimate expected return. The return for a given time series is calculated in [annualized discrete terms](/expected-risk/annualizing-volatility-and-return.md). ### Missing Data To account for missing or incomplete data, select “Use Maximum Likelihood Estimators.” ![Historical estimation options](/files/-MEyN0uTEvYfqJrHS1Fe) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://wpahelp.windhamlabs.com/expected-returns/historical-returns.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.