Americans feel stressed. Conventional wisdom says that longer working hours cause this pressure. But the best data show that the number of hours most Americans work has changed little.

Yet adults in many dual-earner families genuinely do feel stressed and pulled in too many directions. Work alone is usually not the reason. The reason rather is that the fundamental arithmetic of the family has changed.

The traditional family operated with two jobs and two adults. The husband had a full-time paid job in the world of work, while the wife had a full-time unpaid job -- bringing up the children, developing ties with the community and taking physical care of the home. In today's two-career family, there are three jobs, two paid and one unpaid, but still only two people to do them.

This problem is usually discussed in terms of gender equity, as women typically do much more than half of the third unpaid job. But there would still be too much work if we had perfect gender equality and each person did one paid job and half the third unpaid job.

What can we do? Traditionalists argue that women should return home, restoring the traditional ratio of two jobs, two adults. Others push for government-supported child care in an attempt to outsource part of the home job and facilitate both parents working outside the home. We believe what is needed are better opportunities both at home and at work, so that families can chart their own directions. Some families will want to spend more of their time on work. For women in many of these families, professional status and separate earnings streams are important. These families need ways to simplify or outsource many aspects of their home jobs.

Others will want to spend more of their time on family, and will need to have part-time careers to facilitate the roles they want to play at home. This is especially likely for some of the most stressed families, those with young children. Many families will want one thing at one time in their life and something else at another.

But while the arithmetic of the family has changed fundamentally, the institutions of the workplace, home and neighborhood have not. Workplaces mainly have the structure they had when all employees were full-time males. They are intolerant of part-time employees, who often function without benefits and without a reasonable career path.

Home and neighborhood have also failed to adapt. Repair services and land-use patterns continue to assume full-time homemakers who can wait at home for repairs, run the house, buy groceries and chauffeur the children. Child care is still personal, unorganized and catch as catch can.

Work is still governed by employment law forged more than 60 years ago to address primarily the 40-hour-a-week full-time employee. Self-employed workers have neither unemployment insurance nor worker's compensation. Yet many families find that self-employment for at least one partner provides the autonomy and the flexible work level they need.

As a society we can do better. At minimum, better part-time careers need to be made available. Rather than talking of simply full-time versus part-time jobs, we need variable careers. And these careers must allow a workload that might change from year to year depending on the nature of the work and the nature of one's life. Employers, for whom the 40-hour week was once a mandated novelty, will need to put into place a more continuous framework.

At home, we need to rethink how services are provided. Resort communities provide one model to pursue. Homeowners could contract, in effect, with a service that assumes overall responsibility for the physical maintenance of the home. Bonded workers would have access to the home to handle regular maintenance, food shopping, as well as handyman work. Businesses offering integrated home care services should find an open market.

These are only examples. There is much more that can be done. We strongly believe that America needs to adapt, and can adapt, both in the workplace and at home. Doing this will create a better life for all hard-working families of two people and three jobs.

Kathleen E. Christensen directs the program on working families at the Alfred P. Sloan Foundation. Ralph E. Gomory is president of the foundation, and a former senior vice president of IBM.