Given that call signs follow a specific prefix and suffix, it is possible to roughly assess qualifications based on the order in which they were issued. The current issuance of call signs across different regions generally adheres to the following standards.

However, there are exceptions:
In the early days (early 1990s), the first group of HAM operators directly used the "BA" prefix (such as Teacher Tong's BA1AA). Later, this was gradually standardized, with different prefixes being assigned to different levels.(BG/BD/BY)This resulted in differences between early and later call signs, making it impossible to solely rely on prefixes to determine qualifications. Furthermore, the timing of call sign issuance varied among different radio management agencies, with some regions issuing them earlier than others. Therefore, even if two call signs share a prefix, the corresponding HAMs may have different qualifications depending on their location and experience.
In summary, after a while of using it, you will gradually become familiar with the local call signs and seniority system. 73