Effective sequence is a method of tracking more than one event on the same effective date (Human Resources). Generally sequence numbers start at 0 and increase by 1 for each separately recorded event on the same date.

For employee job data, every job data record also has an effective sequence number. This effective sequence number allows for more than one action to be recorded on the same effective date. Every action occurring on the same effective date will have a unique sequence number which determines the order in which the actions occur. The highest sequence number with the most recent effective date indicates the record with the current job or person data.

Every transaction on an employee’s job record must have an effective date and an effective sequence.

Example:

An employee has been hired for a one-year contract with a start date of January 1, 2022 and an end date of December 31, 2022. This is recorded as:

• a hire transaction with an effective date of January 1, 2022, with an effective sequence of zero (0) as this is the only transaction on the employee's job record for that day. 
• a termination transaction will have an effective date of January 1, 2023, with an Effective Sequence of zero (0). 

At the end of the contract, the employee gets a renewal of the contract for another year. This is represented by a re-hire transaction with an Effective Date of January 1, 2023, and an Effective Sequence of 1.

Both the termination and re-hire occur on the same effective date but with different Sequence Numbers. Therefore on or after January 1, 2023, the employee is considered active because the current record is the one with the highest effective sequence number. It remains the current record until the next transaction that changes the employee's status occurs.