Advisors who are helping clients avoid running out of money before they die can best solve the retirement income problem by balancing client spending goals with available assets and liabilities, said Russell Investments researchers in a report released Thursday.

Russell's research paper, "Adaptive Investing: A responsive approach to managing retirement assets," calls for shifting from an asset-only view of portfolio management to a broader approach that focuses on:

• A funded ratio that compares assets to liabilities, resulting in a single surplus or shortage number that determines spending needs and retirement readiness
• The risk of outliving assets, guided by wealth, spending needs and lifespan of the investor
• The option to buy an annuity later if needed

"Retirees consistently express three primary needs concerning retirement wealth management: they want low risk of outliving their assets (sustainability), consistent income (predictability), and financial flexibility (liquidity)," write authors Sam Pittman and Rod Greenshields in the report aimed specifically at financial advisors who are helping individual clients meet their retirement income needs. "As investors seek advice, financial advisors that deliver retirement solutions to meet these needs will better serve their clients, thus strengthening their practice."