1) I think employee numbers should remain numerical except in case of organizations with different business units. If the organization doesn't have any business units, just 1 constant prefix of alphabet characters (max 3) should be fine. If organization has business units, then 3 chars from each business unit should be the prefix for an employee number.
Example:
*an organization called Sutra Services Pvt Ltd (with NO business units)
SU
*if same organization has multiple business units, say, SutraHR, SutraLite and sumHR:
SHR
SLI
SUM
2) post the prefix, everything should be numeric/numbers. I think the best way to do this is, follow the below order: "Year-Month-Date-Number"
example:
SU130617001
or
SHR130617001
3) I have seen companies also trying to include Level/Grade within the employee number. However, I don't see any real reason why it would be useful to keep grades within the number. The number is unique enough with the above format, and for assigning a grade you can include a separate column in the spreadsheet or if you're using a software, it should be able to give you another extra field for employee data
4) Final point, no 2 employees should ever have to same employee ID/Number. The whole concept of employee number/ID is a unique identity. This identity will be useful not only when the employee is working in your organization, but also in future when he/she may not be with you. So all records, history, data will be linked with the same iD for life in your organization. Any mix up will causing unnecessary confusion and loss of data.
Example:
*an organization called Sutra Services Pvt Ltd (with NO business units)
SU
*if same organization has multiple business units, say, SutraHR, SutraLite and sumHR:
SHR
SLI
SUM
2) post the prefix, everything should be numeric/numbers. I think the best way to do this is, follow the below order: "Year-Month-Date-Number"
example:
SU130617001
or
SHR130617001
3) I have seen companies also trying to include Level/Grade within the employee number. However, I don't see any real reason why it would be useful to keep grades within the number. The number is unique enough with the above format, and for assigning a grade you can include a separate column in the spreadsheet or if you're using a software, it should be able to give you another extra field for employee data
4) Final point, no 2 employees should ever have to same employee ID/Number. The whole concept of employee number/ID is a unique identity. This identity will be useful not only when the employee is working in your organization, but also in future when he/she may not be with you. So all records, history, data will be linked with the same iD for life in your organization. Any mix up will causing unnecessary confusion and loss of data.