Across the first half of the 20th century, the rate of cardiovascular disease in the United States continued to increase. The mortality was measurable. The causes were less evident. To explore these unknowns, a longitudinal study was initiated in 1948 to measure the health and lifestyles of people in Framingham, Massachusetts. Almost 70 years and three generations of participants later, information gleaned from the Framingham Study – perhaps the most recognized and critical longitudinal study in modern medicine - has revolutionized heart disease prevention by identifying common risk factors: obesity, smoking, high blood pressure and high cholesterol among them.

One can only guess at what the state of medicine and preventive health would be today had the Framingham Study never been launched.

Today, the medical and social dilemmas of how to best serve those with autism parallels the state of knowledge about heart disease in the mid 1900’s. The outcomes of unemployment and lack of continued postsecondary education are measurable. The clues about what interventions, exposures, experiences, and other factors lead to positive outcomes for some with autism but not for others remains a mystery.

One of the things we grapple with at the Life Course Outcomes Research Program is the “What next?” question. We ask this in regard to the direction of our own research program but also at the broader level of autism services research as a whole. What answers do we need to move quality of life forward for adults with autism?

There is a set of questions that can be answered with the available array of short-term study methods. We can determine which interventions and medications work for particular subgroups of people with autism. We can describe what people’s needs are in comparison to the services they are receiving at a particular point in time. And more, but the “more” that we can learn through short-term studies is limited.

There is also a set of questions whose answers depend upon longitudinal study. These are the answers that, similar to the knowledge generated by the Framingham Study, have the potential to effect real changes in the quality of life for the half million individuals with autism who will enter adulthood over this decade.

What are those questions? We offer a sample of critical questions that we believe could be answered with a longitudinal study. The list is not comprehensive, but is meant to drive discussion and spur thinking.

• How do early experiences with families, communities and policies affect the quality of life for individuals with autism later in life?
• How, and in what ways, do employment, independent living and higher education predict later quality of life?
• How often do people cycle in and out of jobs or return home after living independently?
• What are the early signs of co-occurring mental health conditions in people with autism, and what effect do these have on later quality of life?
• How do service needs change over time and across the life span?
• What are the long-lasting effects of interventions?

These are critical questions that can’t be answered with one-shot studies. If we want to change lives, we have to follow people over time to understand how their lives unfold. Longitudinal studies are important for several reasons. First, they can detect individual or group-level changes in behaviors, thoughts and quality of life. This information can lead to more targeted interventions and services. Second, longitudinal research can track the long lasting effects of programs and services, where cross-sectional studies cannot. Finally, longitudinal research studies can link specific early life experiences to later quality of life because information is collected over a long enough time period for the consequences of these experiences to manifest.

If we do not invest in longitudinal research studies, we risk losing valuable information that can improve autism policy and practice. We know that individuals with autism have a different developmental track than their peers in other disability groups and in the general population. We need to identify what these differences are - and when they occur - in order to develop policies and programs that fit the unique needs of these individuals.

Anne Roux, MPH, MA is a nationally renowned autism researcher, author and family advocate. She leads the production of our National Autism Indicators Report series and other publications.

Kristy Anderson, MSW is a PhD student at the University of Wisconsin, Madison. Her research focuses on the definition and measurement of quality of life in young adults.

Paul Shattuck, PhD, director of the Life Course Outcomes Research Program, studies experiences and services promoting positive life outcomes for people on the autism spectrum, their families and communities.