I addressed that in my comment. Their numbers are practically identical, but their conclusion is different, because they make a determination on whether a car seat was "seriously misused".
Further, Table 1 says that seat belts had a non-fatal rate of 99.89% and restraint systems had a non-fatal rate of 99.88%.
Hell, they flat-out say that they had to adjust it to get those numbers:
"Table 2 summarizes little difference in the unadjusted risk for death between users of child restraint systems and users of seat belts (RR, 1.03; 95% confidence interval, 0.72-1.46). After adjusting for seating position, vehicle type, model year, driver and passenger ages, and driver survival status, children in child restraint systems had a 21% reduction in risk for death compared with children in seat belts, although this difference was only marginally significant (RR, 0.79; 95% confidence interval, 0.59-1.05). After excluding the cases of serious child restraint system and seat belt misuse from FARS, children in child restraint systems had a 28% reduction in risk for death compared with children in seat belts (RR, 0.72; 95% confidence interval, 0.54-0.97)."
It seems that they are trying to get to that conclusion.
The result still seems compelling to me. If I can reduce the risk of my child being killed in a car accident by 28% (even if the raw numbers are small) I'm going to do it.
I don't want to change the goal posts here, but death isn't the only thing these booster seats protect against. A properly used booster seat reduces the relative risk of non-fatal injury by more than half[1]. That is also extremely compelling to me.
"Further, Table 1 says that seat belts had a non-fatal rate of 99.89% and restraint systems had a non-fatal rate of 99.88%."
Um, no, I'm afraid.
Table 1 describes the characteristics of the data set. 99.89% of the "seat belt" sample were non-fatal accidents and 0.11% were fatal; that and the row immediately above it sum to 100%. A fatal accident is defined as one in which someone died, including a pedestrian.
"Within FARS, we identified 7813 children aged 2 through 6 years who were vehicle occupants restrained in a child restraint system or a seat belt in a nondrivable passenger car, van, pickup truck, or sport-utility vehicle that was involved in a crash with at least 1 passenger fatality between 1998 and 2003. Of these 7813 children involved in fatal crashes, 1096 children (14%) were killed."
You will then note that in Table 1 for "Overall" the Fatal rate is 1096 (identical to the number of children, the 14% above, that were killed).
You will also note that if you add together the FARS and NASS CDS numbers you will get 9246, which is the total number of children aget 2-6 from both and also the sum of 1096 and 8150 from the "Overall" column on Table 1.
now that I think about it, it doesn't even matter. If the same relative rates are fatal and non-fatal (separately) that still says that they are practically equivalent.
Further, Table 1 says that seat belts had a non-fatal rate of 99.89% and restraint systems had a non-fatal rate of 99.88%.
Hell, they flat-out say that they had to adjust it to get those numbers:
"Table 2 summarizes little difference in the unadjusted risk for death between users of child restraint systems and users of seat belts (RR, 1.03; 95% confidence interval, 0.72-1.46). After adjusting for seating position, vehicle type, model year, driver and passenger ages, and driver survival status, children in child restraint systems had a 21% reduction in risk for death compared with children in seat belts, although this difference was only marginally significant (RR, 0.79; 95% confidence interval, 0.59-1.05). After excluding the cases of serious child restraint system and seat belt misuse from FARS, children in child restraint systems had a 28% reduction in risk for death compared with children in seat belts (RR, 0.72; 95% confidence interval, 0.54-0.97)."
It seems that they are trying to get to that conclusion.