THE recent tide of corporate layoffs sends a bleak message to working Americans not only about their job security, but also about their retirement income."We're getting a lot of people who are disappointed, angry, and worried" about their pensions, says Karen Ferguson, director of the Pension Rights Center in Washington, D.C. The nonprofit, public-interest organization counsels people about their pension rights. Inquiries have mounted in the recession, Ms. Ferguson says. She and other experts raise several concerns: * Changing employment patterns, including layoffs resulting from corporate restructurings, mergers, leveraged buyouts, and the recession, mean that many millions of workers have changed employers in the last decade, often several times. Their retirement benefits are likely to be smaller than those of people who work for a single employer for their whole career. * Employees today bear more of the burden of planning for their own retiremen and are often ill-prepared to do so. * As job-switching makes retirement savings available to workers in lump sums, the temptation to spend the money on other needs increases. Beyond these trends, 45 percent of the full-time labor force is not covered by any private retirement plan. And demographic data suggest that the federal government's Social Security system may be strained in the next century as the ratio of workers to retired Americans narrows. "There is a very real problem - masked to some degree because everybody's first concern is ... keeping a job," Ferguson says. Most Americans are covered by Social Security, but many regard that pension as inadequate. In one typical type of private plan - known as a "defined-benefit" system - the size of one's pension varies dramatically depending on years of service at a company, says Jim Klein, a vice president of Towers Perrin, a benefits consulting firm. In these plans, which cover more than half of the 51 million workers enrolled in some sort of private retirement scheme, the employer pledges a set benefit - for example 1.5 percent of an employee's salary times his years of service. Mr. Klein describes a hypothetical case of two workers who each work for 20 years and reach a salary of $100,000. The worker who stays with one company for 20 years becomes eligible for a $30,000 pension; the other worker, who splits the time between that company and another one with the same pension policy, accrues less than $23,000. "If you're laid off in mid-career, the actual benefit you get" is small compared to those who stay longer with the company, Ferguson says. Some trade unions have negotiated deals so that this slippage in benefits does not occur as long as one switches employers within one industry. A different type of problem crops up in the other main type of retirement benefit, the "defined-contribution" plan, says Dallas Salisbury, president of the Employee Benefits Research Institute. Here, participation is often optional, in contrast to the automatic enrollment in most defined-benefit plans. Mr. Salisbury says the participation rate is only 60 percent in the average 401(k) (one type of defined-contribution) program. In these plans, the employer offers to contribute a percentage of a worker's salary (such as 4 percent) into a fund, and the employee also contributes. By 1987, defined-contribution plans were the primary private coverage for 32 percent of all United States retirement plan participants, up from 13 percent in 1975. "We're moving from traditional pensions to do-it-yourself savings plans," Ferguson says. Many companies only contribute if the employee is also contributing, she notes. Thus, millions of workers - particularly those with low income - are more likely to lack adequate income when they retire, Ferguson says. In addition, many workers who do participate in such plans fail to actually keep the money until retirement. As workers change jobs, their 401(k) savings are typically paid out in a lump sum. In 1988 only 11 percent of lump-sum recipients rolled the money over into another retirement plan, Salisbury says. The rise of lump-sum payouts during the course of one's career, rather than receiving an annuity that begins upon retirement, is the most prominent trend in retirement benefits, he says. He adds that this change need not reduce the pool of retirement savings as long as workers (1) roll the money into a new retirement account and (2) invest the money wisely. But this places a great burden on many people who are used to managing monthly budgets, not managing retirement funds over many decades. "Most people are very poorly prepared to manage money," says Mary Adams, an actuary with Buck Consultants in New York. Congress may consider legislation this year to extend retirement coverage to more Americans by making it simpler for small companies to set up 401(k) plans. Ferguson suggests the US follow other industrial countries by either requiring employers to sponsor retirement plans or expanding Social Security coverage.