Brett Favre is the worst quarterback of all time. That is what one statistic tells us. And elevated blood lead levels are responsible for IQ falls. And benzene caused the leukemia. For those of you who missed our Tiger Woods story in a recent e-Report, the response was exceptional. I shall amplify upon it with another sports analogy. Even before the end of his subpar 2008 season, Brett holds the all time interception record. He has thrown 305, but he has a good many other records as well:
| Interceptions |
305 |
Most ever |
| Completions |
5682 |
Most ever |
| Consecutive Regular Season Starts |
269 |
Most ever for a quarterback |
| Passing Yardage |
64,707 |
Most ever |
| Passing Touchdowns |
463 |
Most ever |
So, when we look at the totality of his record, Brett Favre turns out to be one of the greatest quarterbacks ever, even though he has one bad statistic – interceptions.
When many factors (known as variables) have an impact on an observed outcome, epidemiological studies evaluate the impact of that factor by controlling for the other variables.
Lead is to a child's IQ as Brett Favre's interception record is to his standing as a quarterback. Although that individual record was poor, it is irrelevant to Brett Favre's overall record as one of the best quarterbacks ever. The same is true for a lead level in a given child. The attributable risk of lead to IQ is,
approximately, 4%. This means that 96% of a child's IQ is determined by factors other than lead. Studies which fail to control for those factors cannot find a lead effect. It simply disappears in the noise. The statistical methodology by which this is done is known as "multivariate analysis." Any attorney dealing with studies which use multivariate analysis (not just lead, but cancer causation and numerous others) must become familiar with this statistical methodology. Most of your opposing experts will not be. Those factors cannot be and are not
controlled for in an individual claim. Some of those factors routinely controlled for in lead toxicity studies, but not in claims (they cannot be) include, among many others:
-
Parental IQ
- Parental occupation
- Home Life
- Socioeconomic status
- Birth Status
- Maternal activities in pregnancy
- Nutrition
So, the next time you are told that lead was responsible for decreased intelligence and/or bad behavior in a child, you will know that there is no possible way that an expert can extrapolate from the literature to the child about whom he/she is testifying. Further discussion of this is available by contacting me at info@nmas.com.
Ronald E. Gots, M.D., Ph.D.
THE NMAS GROUP
2301 Research Boulevard
Suite 210
Rockville, MD 20850-3204
800-566-1669
info@nmas.com
