Under a "Defined Benefit" scheme, the retirement pension earned by a member for each year of service is defined at the outset in the scheme rules using a specified formula and the ultimate level of pension is based on the member's earnings and service to retirement. Importantly, the pension entitlement is not linked to the investment return achieved on the pension scheme assets (and the risk of poor performance is borne by the sponsor).
Specifically, these are typically either Final Salary (pension based on final salary at retirement) or Career Average (pension based on average earnings over career), and the pension is paid for the member's life.
By contrast, under a "Defined Contribution" scheme, the sponsoring employer and the member pay a defined level of contributions into the scheme.
The ultimate level of retirement pension the member receives depends directly on the investment return achieved on those contributions within the scheme and on the cost of any investment products purchased by the member at retirement.
The member typically has the flexibility to choose the form of the pension income in retirement.