The main differences between the period indicator and the time indicator are:

1. Different additivity. The periodic index can be accumulated vertically, and the total index of another longer period can be obtained by adding the periodic indexes adjacent in time. It can also be accumulated horizontally, and the periodic indicators of the same nature but different groups can also be accumulated. It is generally meaningless to add the values of two indicators at different time points. However, the index values at different time points can be added at the same time point of the same nature.

2. The value of the period index is directly related to the length of the period. Generally speaking, the longer the period, the greater the index value. The value of the time point indicator has nothing to do with the interval of registration time.

3. The cycle indicator value must be recorded continuously. The value of the cycle index depends on the development of each moment in the whole cycle, and only the cycle index obtained by continuous registration will be accurate. The index value of time point is generally obtained by intermittent counting. Time point indicators do not need to be registered continuously, and some of them are impossible to register continuously.

4. The cycle index belongs to the flow index, and the time index belongs to the stock index.

5. They have different meanings.