That makes them useful tools in recruitment and retention, particularly since, according to the firm's most recent Global Benefits Attitudes Study, "globally, employee desire for retirement security and guaranteed benefits has never been higher."

Since so few DC plans offer guaranteed benefits as an option, whether through annuities or some other means, that leaves DB plans as king of the hill in that respect—something many employers have noticed.

But employers still have to make sure those plans are sustainable.

Such factors as cost have to be managed over the long term.

To that end, Willis Towers Watson has put out a checklist of 10 steps plan sponsors can take to make sure their DB plans are sustainable.

1. Compliance/governance.

Plan sponsors need to establish and document their compliance processes, including how they make decisions.

"A written governance framework," said the checklist, "will encompass people, processes and procedures," which will aid organizations in making DB plan management decisions quickly, consistently and effectively.

Among the factors to be included in that governance framework are "clearly defined responsibilities for plan document compliance, fee benchmarking, administrative practices, and legislative and regulatory changes."

2. Plan design.

The way a plan is designed, the checklist said, should support the firm's employee benefit philosophy.

In addition, it should efficiently use the sponsor's investment, as well as encouraging employees to retire once they've hit that retirement readiness milestone.

But it doesn't end there; sponsors should continue to evaluate the design of their plans as demographics, market conditions, legislation, regulations and the competitiveness of benefits change.

3. Administration.

Data quality is an important factor not just in processing transactions, but also in forecasting the financial impact on participants that any potential plan changes may have.

Sponsors need to be sure that the quality of plan data is held to high standards—in particular participant data.

4. Communication.

Direct communications, via targeted tools and communications that are segmented to various groups within the employee population, are more effective in helping participants to understand the value of their DB plan.

In addition, the timing of such personalized communications—relating to key life events—will enhance their understanding and appreciation of the plan.

5. Plan assumptions.

Sponsors should make sure they periodically review plan assumptions.

Changes in everything from market conditions to plan experience and legislative and regulatory changes can affect how DB plans work over time.

Reviewing the effects of all these factors will ensure that assumptions about the plan's effectiveness are based on the most recent information.

6. Plan costs.

Sponsors often know some of the costs incurred by the DB plans they offer, but seldom know all of them.

They need to look at factors other than fees when determining the true bottom line: such things as economic cost, benefit cost, administrative fees, Pension Benefit Guaranty Corporation premiums, and investment management expenses are all part of the total.

In addition, plan cost must be considered in any strategic review of all plan management activities.

7. Plan funding.

The checklist points out that any short-term benefit gained by skipping a plan funding contribution, even if it's not required, can not only increase subsequent contribution amounts, but also end up costing plan sponsors far more in the end—often at the worst time possible for the sponsor.

Funding policies will differ from plan to plan and from industry to industry, but a long-term funding policy will make sure that contributions are made on a regular basis and that unpleasant surprises don't lie in wait down the road.

8. Plan liabilities.

Plan sponsors should be on the lookout for opportunities to cut plan liabilities.

The checklist suggests, "Consider making periodic, small-amount bulk lump-sum sweeps or an ongoing lump-sum offer as an effective and cost-efficient way to reduce liability when conditions are right."

9. Investment policy.

The plan's investment policy should be in alignment with the plan itself, and with the objectives of the business.

In addition, plan sponsors should be clear on goals for investment return and risk tolerance, since these too have to be taken into account when aligning investment policy and business objectives.

10. Risk tolerance.

The plan's risk tolerance, including equity exposure, must be defined and monitored.

According to the checklist, "Many organizations change their viewpoint on how much risk they want to take after modeling their risk tolerance.

Some see that they can afford more risk than they thought." Even so, continuing to monitor risk tolerance is essential lest circumstances change.