Probability and Health Message Impacts

Like many Americans, recently I received a flu shot.  As far as I can recall, I've never had the flu; some years I've been vaccinated and some years not.  It is a calculated risk either way.  If you don't get the  vaccine, you may not get the flu.  If you do get the vaccine, you may have immunity with no symptoms, mild symptoms, or severe side effects.  Those severe side effects are very rare, while around 35,000 Americans die each year from influenza infection.  The odds are in favor of those who are vaccinated.  Nevertheless, it is a hard sell for the public.

This is similar to many health promotion measures.  Every year there are deaths of people who are out exercising and in the process have a fatal heart attack.  Statistically, it is probable that vigorous exercisers will have many health benefits, including longer life.  However for some the probability will fail and they will suffer harm which might have been avoided if they were more sedentary.

There are a couple of problems with playing probabilities to promote health.  For many people a partial promise is not very motivating.  They want absolute assurance: if...then.  Of course, health is not like that; there are few if any guarantees.  From a practitioner's perspective, it is difficult to bring about change if you are only able to offer a 30% reduction of risk, for example.  Unlike business promoters, we are constrained by ethics to be truthful, even when it blunts the health message.

Another complication is when money and resources are an issue.  I have a family member who has a close family history of colon cancer.  This person is very worried about risk for colon cancer - not an unreasonable concern.  Many insurance carriers, including hers, do not cover colonoscopies for people under 50, because the "harvest" of possible cases found is very low.  In other words, if the insurer provides a colonoscopy for every 50 year old, enough full-blown cases of colon cancer will be prevented, so that the cost of screening is less than the cost of treating all those cases that would not have been prevented.  At 40 or less, too few cases will be prevented to justify the business expense of screening, even though people like my relative would benefit, perhaps even to a life-saving extent.

On the one hand, someone might condemn a system that doesn't put lives always first.  On the other hand, one might believe that resources, even in health care are finite; we have to use investments in prevention and treatment in such a way to protect and promote health most effectively for the most people.  Both sides of the argument have merit.  However, the issue here is not to screen or not to screen, but the difficulty of crafting public information messages to address these and many more health matters.

Communication to the public will be more effective if messages are clear, uncomplicated, direct, and unequivocal.  One of the hardest tasks of health promotion is to communicate effectively when none of those qualifiers apply.  This is a partial explanation for 45 million smokers after 50 years of communicating an anti-smoking message.  In the face of this reality, we can take much satisfaction that there are 5 million fewer smokers than we once had.

Fortunately, there are many theories which can be used to do battle against resistance to health communication.  For example, if you want to promote flu vaccination, should you say 1) Physicians recommend the vaccine; 2) If you don't get vaccinated you might die; 3) Most of your friends are getting vaccinated?  Theories shed light on whether one or more of these approaches will be most effective.  In addition, there is a geeky sounding field of research and practice called decision science.  It doesn't get much public attention, but is learning more and more about how and why people make the decisions they do, and how to tip decisions toward health promoting action.  This field will provide more tools for health promotion in the future.  The next time you see or hear a health message, you might wonder what marionette is behind the scenes trying to help you protect your health and promote your wellness.