In a Ph.D. prospectus a student apparently said "Every year since 1950, the number of American children gunned down has doubled."
This he apparently got from a scientific journal which in turn reworded a statement made by Children's Defense Fund in 1994 - "The number of American children killed each year by guns has doubled since 1950."
Quite a bit different.
The author points out the two blatant mistakes - one of geometric progression - if the number had truly doubled every year, it would by now be in the trillions.
The other mistake is not really a mistake but an omission - the overall population increased 73% over that period or almost doubled and with higher proportion of overall population being children, the number of deaths caused by guns may not have proportionately increased at all.