Monthly Archives: August 2014

Association Does Not Equal Causation

Here is the claim: “Running 5 minutes a day could add years to your life.”

And here is how it was reported on the Time Magazine Website:

According to a new study published in the Journal of the American College of Cardiology, running 5 minutes per day can reduce an individual’s risk of premature death by about 3 years. Researchers found that people who ran less than an hour per week also saw an increase in lifespan, not just a decrease in risk of premature death. The study took place over the course of 15 years, testing participants ranging in age from 18-100.(

The basis for the headline is an article published in the August 2014 Journal of the American College of Cardiology (ACC) written by researchers from several universities (including the University of South Carolina) who used a database of information about people who were treated at the Cooper Clinic and the Cooper Institute in Dallas, Texas, since 1970.  The some of the information in the database was collected by asking Cooper patients to complete a questionnaire about their physical activity; for example, what kind of exercise do they do, how often, and for how long. They are also asked health related questions about smoking, alcohol consumption, diet and so forth. 

The research question for the investigators was “what behaviors of the sample population were associated with a reduction in premature death?”

First, they selected a random sample 55,000 records that were taken at least fifteen years ago, including both men and women, ages 18 to 100, with a mean age of 44 years of age.

The investigation proceeded to do a search of death records to identify the subjects who may have died, the age of death to determine whether the death was premature, and the cause of death. 

It was found that 3,413 of the 55,000 subjects had died of all causes with 1,217 deaths attributable to cardiovascular factors.

The behavior that was associated with a reduction in premature death was running. Running was associated with a reduction of 30% in deaths from all causes and 45% reduction in deaths from cardiovascular causes.

The surprise finding was that it didn’t seem to matter whether the running was done for fewer than 51 minutes per week or at a pace of less than 6 miles per hour (10 minute miles). In addition, the runners who had identified themselves as “persistent” runners, had a reduction of 50% fewer premature death attributable to cardiovascular problems.

The statistical analysis of the data identified correlations among the factors. Correlation finds factors that vary together; an increase (or decrease) in one factor is associated with an increase (or decrease) in another. In this case, running was associated with a decrease in premature death.

Correlation is a powerful tool but it comes with a caveat: correlation can identify the strength of an association but it cannot tell anything about why two factors are related. The caution is therefore not to attribute the relationship to cause-and effect. 

So while physicians and health care workers should certainly share the association to encourage the large numbers of Americans who are sedentary to become more active, the actual mechanisms are yet to be fully researched.


You can find the abstract and additional information about Leisure-Time Running Reduces All-Cause and Cardiovascular Mortality Risk on the American College of Cardiology Website.

A technical discussion of correlation may be found in Stephen Jay Gould’s The Mismeasure of Man, Revised and Expanded Edition, W.W. Norton & Company. New York. 1996. pp. 269-285.


An Ounce of Intervention is Better than a Pound of Remediation

“Science often involves the construction and use of a wide variety of models and simulations to help develop explanations about natural phenomena. Models make it possible to go beyond observables and imagine a world not yet seen.”

Although the achievement gaps between ethnic groups have been reduced over the past half-century, those that are tied to family income have actually widened. Children whose family income is less that 200% of the federal poverty rate are more likely to have lower school achievement as measured by test scores, are less likely to enroll in post secondary programs, and are less likely to form stable families as adults. Note that the problems faced by children are still there, although in different form, when those children grow up.

This posting provides an example of how the construction of a model based on real world data can be used to help understand the both nature of a problem as well as help identify potential ways to address and solve the problem.

The Brooking Institute’s Center on Children and Families developed The Social Genome Model (SGM). The SGM is the beginning stages of its implementation and its creators have begun to use it to ask what the world might look like if we could successfully eliminate the income-based gap in early childhood. In this “what-if” experiment, we simulate what would happen if we improved the average chances of school readiness at age five for low-income children so they matched the levels of higher-income children. (

What are the factors in life that make it more likely that the future of a child will be one in which the child will in fact have the opportunity to improve his or her life prospects?

The Social Genomic Model identifies a series of “life stages” in a child’s life along with the criteria that appear to be necessary to be successful at that milestone.

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The good news for children who have pre-reading and math skills (print sense, phonemic awareness, number sense, for example) as well as the social behavior that allows them to work and play well with other children have an easier time being successful in school. More good news: those children are likely to continue to meet the challenges of the next stages more effectively.

The bad news: if a child is missing one or more of the traits, he or she will have a harder time being successful at the initial life milestone. More bad news: each subsequent life milestone will become more challenging.

The SGM is an “if-then?” engine that can generate different scenarios by changing the equations. What if, the equation is changed to include parent training and pre-school?

Low-income Hispanic mothers who were taught Play and Learning Strategies (PALS) were found to increase the emotional support for their pre-school children. The potential of pre-school for four year olds is well-documented.

Teaching parents the PALS and adding it to a pre-school program changes the equation so that children from economically poor families increase the likelihood by 20 percentage points, bringing them almost to the success level of children from the more affluent families.

More good news: according to the SGM data, changing the equation for children through a few interventions have the potential to bring about tangible improvement to those children when they are adults.

Add to the PALS and pre-school, Success for All and Social and Emotional Learning for Middle Childhood and Small High Schools of Choice for Adolescents at a cost per child of $24,900 results in an income change for the children as adults of $132,000. A nice return on the investment!


Improving Children’s Life Chances: Estimates for the Social Genome Model.

Center on Children and Families at the Brookings Institution

The Social Genome Project.