The "alpha value" is a measure used in finance to evaluate the performance of an investment compared to a benchmark index, such as the S&P 500. It indicates how much an investment has outperformed or underperformed relative to the expected return based on its risk level. A positive alpha value suggests that the investment has performed better than expected, while a negative alpha indicates underperformance. In the context of statistics, alpha can also refer to the significance level in hypothesis testing, typically set at 0.05. This value helps determine whether to reject the null hypothesis, indicating the probability of making a Type I error, or incorrectly concluding that a result is significant when it is not.