It is calculated based on a time range. The click volume in a certain time range divided by the display volume is the click-through rate. If you look at the data of the through train, you can choose the time range yourself, such as three days, a week, or a month. The click-through rate of keywords in the promotion plan refers to the click-through rate of yesterday, and the click-through rate is different every day. The quality score is related to the correlation between categories, attributes, keywords, and other factors. It is an internal factor, and the click-through rate is an external factor. Every word must be carefully taken care of, because you have to continuously optimize it, find patterns in the clicks, which words people prefer, which words are popular but have low conversions and should be pushed secondarily, and which words are unpopular but have high conversions and should be pushed as the focus. Slowly, your words will be divided into echelons. When you first start pushing, all words are equal, but as the click-through rate and conversion rate change day by day, you will choose keywords that are suitable for your own store. This is word cultivation. It is abnormal if there is no change.