Data Protection Principle 4 - Accurate and up-to-date

Data is only likely to be accurate if

• it is accurate when it is obtained, and
• procedures are in place for it to be maintained if it changes.

The effect of this Principle is that, if data cannot be maintained accurately, it should not be kept at all. Inaccurate information about an employee is more likely to cause damage to an employee than not having it at all.

The DPA gives additional guidance as to whether a data controller, in the event of a complaint, has endeavoured to comply with this Principle. Information from an employee or a third party would not be treated as being inaccurate if the employer had taken "reasonable steps" to ensure accuracy. It is routine in payroll offices for the data input of "temporary" data to be checked thoroughly. Compliance with this Principle does not, however, demand excessive checking, only a "reasonable" level of checking. Payroll systems increasingly have validation checks on input, particularly with the introduction of the Inland Revenue's Quality Standard.

Most "permanent" payroll data does not change, but some information does change with time. The most important example is employees' addresses. Unless there is some way of forcing their maintenance, such as posting payslips to all employees, addresses are notoriously inaccurate. There is no statutory requirement to keep addresses - employers are only expected to show addresses on P14s if they are known. If addresses are inaccurate and cannot be maintained accurately, their continued use should be questioned.

Of course, the address may be needed for personnel purposes, in which case "reasonable steps" must be taken to update them. Some employers send a printout of the data held in their personnel and payroll systems to their employees each year in order to improve accuracy. The trend towards self-service gives employees the opportunity to maintain their own personal information. Neither methods are foolproof, however, as they depend on the willingness of the employee to respond.

Another essential check in payroll is to write to women paying reduced-rate NICs each year and ask them to confirm that they haven't lost their entitlement to their election.

Another accuracy problem for payroll offices can exist where they receive transcribed documents from other departments, particularly from the personnel department. For accuracy reasons, and also for sound information security reasons, it is always better to work from original documents. That may require documents to be sent to the payroll department first, and then forwarded to personnel.