Children, Youth and Environments
Vol 13, No.1 (Spring 2003)
ISSN 1546-2250

Do Child Safety Seat Installation Instructions Need to Be Simplified?¹

Mark V. Wegner
Wisconsin Division of Public Health
Deborah C. Girasek
Uniformed Services University of the Health Sciences

Citation: Wegner, Mark V. and Deborah C. Girasek. “Do Child Safety Seat Installation Instructions Need to Be Simplified?” Children, Youth and Environments 13(1), Spring 2003. Retrieved [date] from http://colorado.edu/journals/cye.

Abstract

The objective of the study was to measure the required reading level of a sample of child safety seat (CSS) installation instructions, and compare readability levels among different prices of CSSs. A CD-ROM containing CSS installation instructions was obtained from the National Highway Traffic Safety Administration (NHTSA). Their readability levels were determined using the SMOG test. The study demonstrated that the readability of instruction sets ranged from the seventh to twelfth grade levels, with an overall SMOG score of 10.34. No significant associations were found to exist between readability and seat prices. The authors thus conclude that CSS instruction manuals are written at a reading level that exceeds the reading skills of most American consumers.

Keywords: child safety, car seats

Introduction/Background

Motor vehicle collisions (MVCs) are a leading cause of death in infants and children. In fact, in 1998, injuries resulting from motor vehicle crashes accounted for 46 percent of all unintentional injury-related deaths among children aged 1 to 14 (NCHS 2000). Scientific evidence indicates that the single strongest risk factor for injury in an MVC is the non-use of a restraint (Johnston et al. 1994), with correctly used child safety seats (CSSs) reducing the risk of fatal injury by 71 percent and hospitalization by 67 percent (Kahane 1986). For child restraints to be optimally effective, however, they must be installed correctly. Yet we know from numerous studies that improper restraint use is alarmingly prevalent, ranging from 79 to 94 percent (Decina and Knoebel 1997; Lane et al. 2000; NHTSA 1996).

The underlying reasons for such a high rate of misuse of this important child safety device are not well understood. One possible contributor is poor comprehension of installation instructions. Poor comprehension often occurs when the required reading level of a particular text exceeds the reading capacity of the target population. In this situation, people often become fatigued and discouraged, which may affect compliance (Doak et al. 1996).

This issue is important to consider when developing health-related instructions because illiteracy is a problem of great importance in the United States. A 1992 survey by the U.S. Department of Education's National Center for Education Statistics estimated that about 46 percent of the adult population— more than 90 million Americans over the age of 16 —were classified as being “marginally literate” or below (i.e., they read at or below about the eighth grade level) (National Center for Education Statistics 1992; Doak et al. 1996). The impact of literacy on health has also been well documented in the literature (Weiss and Coyne 1997), and the readability of health-related materials has been the subject of increasing scientific scrutiny (Morrow 1980; Powers 1988; Davis et al. 1994; Wells 1994; Williams et al. 1995). We identified only one article that dealt with child safety and literacy, however, and it did not address CSS installation (Powell et al. 2000).

In this study we measured the required reading level of CSS installation instructions to determine whether readability poses a potential barrier to correct installation. An additional objective of the study was to compare readability levels among different price categories of CSSs. The main reason for this second analysis was to determine if the lower cost seats that are more accessible to low income parents financially are also more accessible to them from the perspective of literacy.

Methods

The instruction sets used for the purposes of this study came from a CD-ROM distributed by the National Highway Traffic Safety Administration (NHTSA) that contains 140 instruction sets for 11 different manufacturers and models current through 1999 (NHTSA 2000). Certain exclusion criteria were applied to the 140 instruction sets to generate our final study sample of 107, and each manufacturer on the CD-ROM was represented with at least one model. Available pricing information for 35 of the CSS models was then obtained from epinions.com (Epinions.com 2001), an internet-based company that provides comparative shopping information for consumers.

The SMOG (McGraw, n.d.) test was chosen for performing readability tests on the samples. The basic provisions of the test include selecting three ten-sentence samples (one each from near the beginning, middle and end of the desired text), and then counting the number of polysyllabic words (containing three or more syllables) in that sample. This information is then used to calculate the reading ability (measured as school grade reading level) required in order for a person to comprehend that particular text.

Ten sentences were tested in three distinct section types that related most closely to the issue of injury prevention. Headings were not tested unless they were part of a sentence. Pictures and diagrams were not considered, nor were captions that stood apart from the rest of the instruction set and applied only to pictures. Federal Law (Child Restraint Systems 2000) mandates that certain language must be included in all instruction sets. These passages were tested separately from the instruction sets and were not included in our statistical analyses.

Basic descriptive statistics were generated, including mean readability level overall and mean readability by manufacturer. Further statistical tests were performed on the subsample of CSSs included in our pricing analyses to determine if instruction readability varied by product price.

Results

The readability scores of the installation instructions we tested ranged from seventh to twelfth grade, with a median and mode of 10 (see Table 1 for a frequency distribution of scores). The overall mean SMOG readability score was 10.34, and the wording sections required by Federal regulation also tested at the tenth grade level. Our subanalysis demonstrated no relationship between CSS price and readability of installation instructions.

SMOG Score	Frequency	Percent	Cumulative Percent
7th Grade	1	0.9	0.9
8th Grade	2	1.9	2.8
9th Grade	14	13.1	15.9
10th Grade	42	39.3	55.1
11th Grade	39	36.4	91.6
12th Grade	9	8.4	100
Table 1. Frequency Distribution of SMOG Scores for Child Safety Seat Installation Instruction Manuals

Discussion

Our data indicate that CSS instructions in the United States are currently written at a reading level that is too high. Experts in the arena of health literacy recommend that materials be targeted to the fifth or sixth grade reading level (Doak et al. 1996; Weiss and Coyne 1997). The average readability level of the instruction sets we tested was tenth grade. Researchers in a Louisiana study found that about two-thirds of parents tested in an outpatient clinic could not read at more than a ninth grade level (Davis et al. 1994). Since parents would be expected to be the main target audience for CSS instruction sets, this lends further evidence that the instruction sets may not be reaching the people most likely to benefit from the message. The fact that reading levels did not differ among price categories of seats suggests that manufacturers are not targeting instructions to different market segments, at least with regard to this indicator.

In addition, parents may not even read the instruction manuals that come with their CSS or may receive second-hand seats that come without instructions, so the importance of instructions in the proper installation of CSS is unclear. In focus groups sponsored by the National Highway Traffic Safety Administration, however, parents reported referring to written instructions when they ran into difficulties (Federal Register 2001).

Education efforts combined with recent engineering advances can be important complements to CSS instruction sets; hands-on instruction has been shown to decrease the numbers of errors in CSS installation (Lane et al. 2000). Information on available seat installation training opportunities throughout the United States is available from NHTSA through its website at http://www.nhtsa.dot.gov/people/injury/childps/Training/index.html or via a hotline at 1-800-424-9393.

Engineering improvements brought about by recently enacted legislation may indeed prove to be the most important factor in decreasing misuse. Uniform standards such as upper tether straps and lower anchorage systems (which allow seats to be virtually snapped in place) have the potential to make CSS installation a much simpler process, requiring very little instruction.

With respect to our testing methods, it needs to be noted that there are limitations inherent in the SMOG readability test. Many common words such as “vehicle,” “serious,” and “injury” were repeated often in virtually all of the instruction sets. Although some may argue that these three syllable words may be easily understood, testing procedures called for them to be counted in the SMOG tally. This most likely increased the overall grade level of the samples. However, it is doubtful that these words alone could account for the fact that the sample’s required reading level was twice what experts recommend.²

Finally, this study also suggests some areas for potential future research. It would be valuable, for example, to evaluate the effectiveness of installation instruction sets. It would also be of interest to see if an association exists between literacy and proper CSS installation and use, and whether misuse patterns are associated with the readability of instruction sets.

Still, it seems advisable from our data that manufacturers of CSS should rewrite their instruction sets to a fifth grade reading level. This could be accomplished by using shorter sentences and simpler words. Subsequent testing could verify whether the desired level of clarity had been achieved. The National Highway Traffic Safety Administration has announced that they will pursue such a process with regard to the language they require manufacturers to put on CSS labels (Federal Register 2002). Manufacturers and regulators may also want to explore whether alternatives to written installation instructions should be made available to consumers.

If the above recommendations are put into practice in the short term, and design improvements are widely adopted in the long term, the prevalence of proper CSS use may increase to a level befitting the importance of this effective injury prevention tool.

Endnotes
1. We would like to acknowledge Susanne Ogaitis-Jones and Julia Alkire for sharing their expertise on CSS, David Cruess for his guidance on our statistical analyses, and the National Highway Traffic Safety Administration for making their CSS instruction collection available and for providing valuable background information on this topic. Julianne J. Brown acted as our second rater of CSS instructions.

The views expressed in this report are those of the authors, not the U.S. government.

2. This study also did not take some factors that tend to increase comprehensibility into account, such as the use of illustrations and empty space (Doak et al. 1996). The main reason this was not done was because images that were generated from the CD-ROM lost resolution.

Mark V. Wegner is the Chief of the Communicable Disease Epidemiology Section within the Wisconsin Division of Public Health. His medical specialty is Public Health and General Preventive Medicine for which he is board certified by the American Board of Preventive Medicine. He received his medical degree from the University of Wisconsin – Madison Medical School and his masters degree in public health from the Uniformed Services University of the Health Sciences (USUHS). At the time this study was performed, Dr. Wegner was an MPH candidate at USUHS.

Deborah C. Girasek is the Director of Social and Behavioral Sciences in the Department of Preventive Medicine at the Uniformed Services University of the Health Sciences (USUHS). Dr. Girasek teaches in USUHS’ graduate program. Her research focuses primarily on the psychosocial aspects of unintentional injury. She received her graduate training at the University of Michigan and the Johns Hopkins School of Hygiene and Public Health.

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