Such manuals are written at a tenth-grade reading level on average, according to a new study, while data suggest that nearly a quarter of U.S. adults read at or below a fifth-grade level, and at least 25 percent read at about an eighth-grade level.
The findings are cause for concern because motor vehicle collisions are a leading cause of death and injury for infants and children. About 80 percent of car safety seats are improperly installed or misused, the study found.
The study, appearing Monday in the March issue of Pediatrics, was conducted by Dr. Mark Wegner and Deborah Girasek at the Uniformed Services University of the Health Sciences in Bethesda, Md.
The Juvenile Products Manufacturers Association, which represents car-seat makers, disputed the findings.
But Joe Colella of the National Safe Kids Campaign, an advocacy group that works with manufacturers on child safety issues, said most are aware of the problem.
For liability reasons, lawyers usually are involved in writing installation instructions, and legal jargon might make instructions sound confusing, Colella said.
Car-seat makers "have made us aware that they're going to rewrite most of their instructions" to make them more readable, he said.
Many city police and fire departments offer help in installing child seats.
Frank Grgas, a firefighter in Gurnee, Ill., said his department gets dozens of calls a month from parents needing help with car seats.
"Ninety percent of them in Illinois are installed incorrectly," he said.
Grgas said he doesn't know if that's because the seats are hard to install, the instructions are difficult or parents just aren't reading them. "I've read through quite a few of them, and some of them can be confusing," he said.
Girasek said manufacturers could help by writing installation instructions at a fifth-grade level, which literacy experts say is optimal for understanding health-related information.
Simplifying car-seat design and installation also might be beneficial, but that would be more costly, Girasek said.
Studies are needed to prove whether either change would affect death and injury rates, but simplifying instructions would be a commonsense "relatively easy fix" in the meantime, she said.
"This could be accomplished by using shorter sentences and simpler words. For example, 'collision,' 'automobile,' and 'remedied' could be replaced by 'crash,' 'car,' and 'fixed,'" according to the study.
The researchers analyzed installation instructions from every major child safety seat manufacturer for models through 1999.
They found instructions written at reading levels ranging from seventh to 12th grade, based on a test used extensively to analyze readability of health literature. Reading difficulty was tied to the number of words with three or more syllables appearing in 10-sentence samples.
Readability was not significantly related to cost; car seats ranged in price from $58 to $207.
By Lindsey Tanner