Basic concepts of codification

As we read above, it is evident that there needs to be some way to identify the items uniquely, accurately and adequately. These attributes of identification can be achieved through proper classification and codification. For instance, we are aware of the PIN Codes set by Post and Telegraph Department to distinctively and concisely identify different regions of the country. Codification is referred to the procedure of signifying each item through a group of numbers and alphabets that indicates the group, subgroup, kind and dimensions of the items. Most of the organizations from the public and private sectors, railways, etc. have their own established codification systems. Coding may have number of digits varying from 8 to 13. Coding symbols can be arranged in various possible ways, which may have numbers, alphabets, alphanumeric characters, and so on. Nevertheless, before a coding scheme is decided, a considerate thought should be given to its design, such that it meets the requirements of the item identification and also satisfies various users.

Following considerations need to be taken into account while designing codes:

Brevity – Avoid giving long, complex descriptions to the codification system. Therefore, the codes should comprise lesser number of digits. The size of the code should be based on the number and types of items, and the number of applications of the related data to the item.

Logical – The coding system should logically fit the needs of the user and that of the data processing methods used.

Flexibility – The design of coding should be flexible enough to cope with changes without altering existing coding. For instance, in a library, the coding is never affected by addition of new books, and thus, upcoming books can be easily accommodated by the current code structure.

Exclusivity – The code for each item should be able to represent it exclusively. Similarly, an employee identification code should identify not more than one employee.

Easy to Understand – The code structure should be set such that it can be easily understood by its users, and be practical and meaningful.

Right Use of Coding Symbols – A code can have alphabets, numbers or a combination of both, but at the same time, certain precautions need to be taken in selecting the symbols. If the characters appear similar to each other, they should be removed. Also, letters that sound similar should not be used. For e.g. B, C, D, G, P, M, N and T.

Code Layout – The layout for coding should be equivalent in length. For instance, 1-199 should be preferred to 001-199. Codes longer than five characters should be disintegrated into small segments for human judgments.

Code Capacity – To estimate whether the given code has the capacity to cover all situations and yet maintain the code exclusivity, the following formula should be used:

C = SP

Where, C refers to possibility of total possible code combinations available, S refers to the number of unique characters in the set, and P is the number of code positions.

The size of code structure should be decided much before by estimating the need of unique combinations.

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