Option value plays a big role in search. Indeed, if you didn’t have the option to truncate the search, it could hardly be called search. And option value is increasing in the riskiness of the choices—which means that it is better to look at risky choices early in the search process.

It follows that the standard practice of ordering retrieved documents by their expected relevance, or expected value, or any such expectation is not really right. The actual ordering should depend not only on the estimated first moment of the distribution, but on higher moments as well.
—Hal Varian on Search in 1999