The gap magnitude of the opening of the day after the earnings announcement reflects the intensity and direction of the market's immediate reaction to the earnings announcement. A positive gap magnitude (i.e., a positive factor value) usually indicates that earnings performance exceeds market expectations, causing investors to actively buy at the opening of the next day, pushing up the stock price; a negative gap magnitude (i.e., a negative factor value) indicates that earnings performance is lower than market expectations, and investors sell at the opening of the next day, causing the stock price to fall. This factor can be used to measure the impact of earnings announcements on stock prices and can be used as a reference for event-driven quantitative strategies.