The year-on-year growth rate of net profit margin in a single quarter is a commonly used indicator to measure the profitability and growth of a company. It reflects the changing trend of the company's profitability in the short term by comparing the changes in net profit margin in the most recent reporting period with the same period of the previous year. This indicator uses year-on-year changes rather than month-on-month changes, which can effectively eliminate the impact of seasonal factors and better reflect the company's actual profitability growth.

In quantitative analysis, this factor can be used in the following aspects:

• Profitability assessment: A high growth rate usually means an increase in the company's profitability, and vice versa.

• Growth assessment: A sustained high growth rate may indicate a company's good growth potential.

• Stock selection strategy: This factor can be combined with other fundamental and technical factors to construct a stock selection strategy to screen out stocks with strong profitability and growth.

It should be noted that in actual application, it should be considered in combination with the company's industry attributes, development stage, and macroeconomic environment, and other factors, and avoid using this factor in isolation.