Skip to main content
PMC home page
Injury Prevention logoLink to Injury Prevention
. 2002 Sep;8(3):248–251. doi: 10.1136/ip.8.3.248

How old is that child? Validating the accuracy of age assignments in observational surveys of vehicle restraint use

S Moeller 1, L Berger 1, J Salvador 1, D Helitzer 1
PMCID: PMC1730877  PMID: 12226127

Abstract

Objectives: Many large scale observational studies of child restraint usage require observers to estimate the ages of the vehicle occupants. The accuracy of age assignments were assessed and possible methods to improve observational accuracy in research and field studies of child restraint use were identified.

Methods: The validation study was performed at fast food restaurants in a metropolitan area. Three, two person teams observed 449 occupants of vehicles with at least one child passenger. The drivers were then interviewed to obtain the actual ages of the vehicle occupants. The primary outcome measure was the per cent of age assignments that were correct by age category (infant, toddler, school age, teen, adult). The observers had previously conducted a statewide child restraint observation study and were trained in estimating age categories.

Results: A total of 391 (87%) of the 449 occupants were assigned to their correct age categories. Incorrect assignments were more common among infants (22% incorrect), but few infants (nine) were observed. The most frequent error was classifying adults (19 years and older) as teenagers (13–18 years).

Conclusion: Trained, experienced observers approached 90% accuracy in their assignment of children to specific age categories. Additional study is required to determine whether these results are applicable to different age categories and observers.

It is recommended that the National Highway Traffic Safety Administration, the Centers for Disease Control and Prevention, state and local agencies, and other sponsors of observational surveys consider observer competence as an important variable. The validity of age assignments can be assessed by randomly interviewing a sample of drivers. More accurate age estimates will improve decisions regarding prevention programs, funding, and policies.

Full Text

The Full Text of this article is available as a PDF (98.5 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Aekplakorn W., Podhipak A., Khumdee M., Sritamanoj W., Youngkao K., Suriyawongpaisal P., Punyaratabundhu P., Narksawat K., Sujirarat D., Phodaeng C. Compliance with the law on car seat-belt use in four cities of Thailand. J Med Assoc Thai. 2000 Apr;83(4):333–341. [PubMed] [Google Scholar]
  2. Begg D. J., Stephenson S., Alsop J., Langley J. Impact of graduated driver licensing restrictions on crashes involving young drivers in New Zealand. Inj Prev. 2001 Dec;7(4):292–296. doi: 10.1136/ip.7.4.292. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Campbell H., Gorman D., Richardson P. An observational study of car occupant restraint in Fife: impact of recent legislation. Public Health. 1993 Nov;107(6):429–435. doi: 10.1016/s0033-3506(05)80168-4. [DOI] [PubMed] [Google Scholar]
  4. Campbell H., Macdonald S., Richardson P. High levels of incorrect use of car seat belts and child restraints in Fife--an important and under-recognised road safety issue. Inj Prev. 1997 Mar;3(1):17–22. doi: 10.1136/ip.3.1.17. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Centers for Disease Control and Prevention (CDC) Improper use of child safety seats--Kentucky, 1996. MMWR Morb Mortal Wkly Rep. 1998 Jul 10;47(26):541–544. [PubMed] [Google Scholar]
  6. Decina L. E., Knoebel K. Y. Child safety seat misuse patterns in four states. Accid Anal Prev. 1997 Jan;29(1):125–132. doi: 10.1016/s0001-4575(96)00051-6. [DOI] [PubMed] [Google Scholar]
  7. Decina L. E., Temple M. G., Dorer H. S. Increasing child safety-seat use and proper use among toddlers. Evaluation of an enforcement and education program. Accid Anal Prev. 1994 Oct;26(5):667–673. doi: 10.1016/0001-4575(94)90028-0. [DOI] [PubMed] [Google Scholar]
  8. Eby D. W., Streff F. M., Christoff C. A comparison of two direct-observation methods for measuring daytime safety belt use. Accid Anal Prev. 1996 May;28(3):403–407. doi: 10.1016/0001-4575(95)00069-0. [DOI] [PubMed] [Google Scholar]
  9. Ekman R., Welander G., Svanström B. L., Schelp L. Long-term effects of legislation and local promotion of child restraint use in motor vehicles in Sweden. Accid Anal Prev. 2001 Nov;33(6):793–797. doi: 10.1016/s0001-4575(00)00093-2. [DOI] [PubMed] [Google Scholar]
  10. Geddis D. C. How children travel in cars in New Zealand. N Z Med J. 1982 Oct 27;95(718):740–742. [PubMed] [Google Scholar]
  11. George P. A., Hole G. J. Factors influencing the accuracy of age estimates of unfamiliar faces. Perception. 1995;24(9):1059–1073. doi: 10.1068/p241059. [DOI] [PubMed] [Google Scholar]
  12. George P. A., Hole G. J. The influence of feature-based information in the age processing of unfamiliar faces. Perception. 1998;27(3):295–312. doi: 10.1068/p270295. [DOI] [PubMed] [Google Scholar]
  13. Grossman D. C., Garcia C. C. Effectiveness of health promotion programs to increase motor vehicle occupant restraint use among young children. Am J Prev Med. 1999 Jan;16(1 Suppl):12–22. doi: 10.1016/s0749-3797(98)00120-2. [DOI] [PubMed] [Google Scholar]
  14. Laffoy M., Kelly S., Byrne G., Jordan M., O'Herlihy B. Use of seat belts in a Dublin area. Ir Med J. 1997 Apr-May;90(3):103–104. [PubMed] [Google Scholar]
  15. Nelson D. E. Validity of self reported data on injury prevention behavior: lessons from observational and self reported surveys of safety belt use in the US. Inj Prev. 1996 Mar;2(1):67–69. doi: 10.1136/ip.2.1.67. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Petridou E., Skalkidou A., Lescohier I., Trichopoulos D. Car restraints and seating position for prevention of motor vehicle injuries in Greece. Arch Dis Child. 1998 Apr;78(4):335–339. doi: 10.1136/adc.78.4.335. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Pless I. B., Stulginskas J., Zvagulis I. Observed effects of media campaigns on restraint use. Can J Public Health. 1986 Jan-Feb;77(1):28–32. [PubMed] [Google Scholar]
  18. Segui-Gomez M. Evaluating interventions that promote the use of rear seats for children. Am J Prev Med. 1999 Jan;16(1 Suppl):23–29. doi: 10.1016/s0749-3797(98)00118-4. [DOI] [PubMed] [Google Scholar]
  19. Segui-Gomez M., Wittenberg E., Glass R., Levenson S., Hingson R., Graham J. D. Where children sit in cars: the impact of Rhode Island's new legislation. Am J Public Health. 2001 Feb;91(2):311–313. doi: 10.2105/ajph.91.2.311. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Sewell C. M., Hull H. F., Fenner J., Graff H., Pine J. Child restraint law effects on motor vehicle accident fatalities and injuries: the New Mexico experience. Pediatrics. 1986 Dec;78(6):1079–1084. [PubMed] [Google Scholar]
  21. Shope J. T., Molnar L. J., Elliott M. R., Waller P. F. Graduated driver licensing in Michigan: early impact on motor vehicle crashes among 16-year-old drivers. JAMA. 2001 Oct 3;286(13):1593–1598. doi: 10.1001/jama.286.13.1593. [DOI] [PubMed] [Google Scholar]
  22. Steenbergen L. C., Kidd P. S., Pollack S., McCoy C., Pigman J. G., Agent K. R. Kentucky's graduated driver licensing program for young drivers: barriers to effective local implementation. Inj Prev. 2001 Dec;7(4):286–291. doi: 10.1136/ip.7.4.286. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Webb G. R., Bowman J. A., Sanson-Fisher R. W. Studies of child safety restraint use in motor vehicles--some methodological considerations. Accid Anal Prev. 1988 Apr;20(2):109–115. doi: 10.1016/0001-4575(88)90026-7. [DOI] [PubMed] [Google Scholar]
  24. Williams A. F., Wells J. K. Evaluation of the Rhode Island child restraint law. Am J Public Health. 1981 Jul;71(7):742–743. doi: 10.2105/ajph.71.7.742. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Williams A. F., Wells J. K. The Tennessee child restraint law in its third year. Am J Public Health. 1981 Feb;71(2):163–165. doi: 10.2105/ajph.71.2.163. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Winston F. K., Durbin D. R. Buckle up! Is not enough: enhancing protection of the restrained child. JAMA. 1999 Jun 9;281(22):2070–2072. doi: 10.1001/jama.281.22.2070. [DOI] [PubMed] [Google Scholar]
  27. Winston F. K., Durbin D. R., Kallan M. J., Moll E. K. The danger of premature graduation to seat belts for young children. Pediatrics. 2000 Jun;105(6):1179–1183. doi: 10.1542/peds.105.6.1179. [DOI] [PubMed] [Google Scholar]

Articles from Injury Prevention are provided here courtesy of BMJ Publishing Group

RESOURCES