Suppose the exposure only caused a slight increase, only 1.1 times the expected number of lung cancer cases. According to study power calculations, with this amount of increase, the study would only have a 4% chance of detecting an association between the exposure and this slight increase in lung cancer.
Even if there was 2 times the expected number of lung cancer cases, study power calculations showed that the study would only have a 35% chance, which is less than a 50-50 chance, of being able to identify the connection between the exposure and elevated lung cancer rate.
Did they think that it was likely that this exposure was so severe it would cause 3 times greater the number of lung cancer cases in this group than expected? This amount of increase in disease would give a study power that is above 80%.
Researchers determined that the students attending the middle school received a much lower exposure than workers. Researchers concluded that students were probably not exposed to levels of the chemical that are high enough to cause such a tripling in lung cancer rates. Researchers thought it would be more likely that workers handling this contaminant were exposed to high enough levels to cause this large an increase in lung cancer rates. In the future, occupational health researchers may decide to do a health study on how the health of workers has been affected by this contaminant.
What if there actually is an association between the environmental exposure and elevated risk of disease? A study with low power has a small chance of showing an association between the environmental exposure and disease, even though there could actually be one! Thus, such findings may lead to misconceptions that the environmental exposure is not actually hazardous. However, the fact is it may do more harm to produce false results, than to not produce any results at all.
Instead of undertaking a health study, residents organized and conducted a community survey. This survey investigated: 1) how many people in the town knew about the health hazards of the contamination, and 2) how easy it was for people in the town to access to medical care for diseases related to air contamination. This survey determined that a majority of town residents were not aware that the air contamination could be linked to lung diseases. The survey also revealed that there was a lack of local medical professionals trained to identify and treat lung diseases related to this contaminant.
Residents had become a cohesive community group by the end of the survey. This group continued to work together on the important needs identified by the community in the survey. In collaboration with the local health department, this community group organized a series of trainings for local medical providers on lung diseases related to the air contamination, and gave presentations for the general public to increase awareness about lung cancer.