title: The effects of recall on reporting injury and poisoning episodes in the National Health Interview Survey.
abstract: OBJECTIVE
  To examine effects of length of time between injury or poisoning and interview on the number of reported injury and poisoning episodes in the National Health Interview Survey (NHIS). (Hereinafter, both injuries and poisonings will be referred to as "injuries".)
  
  
  METHODS
  The NHIS collects data continuously on medically attended injuries occurring to family members during the three months before interview. Time between injury and interview was established by subtracting the reported injury date from the interview date. Values were multiply imputed for the 25% of the episodes for which dates were only partially reported.
  
  
  METHODS
  An analysis of mean square error (MSE) was used to quantify the extent of errors in estimated annual numbers of injuries and to compare the contributions of bias and variance to these errors.
  
  
  RESULTS
  The lowest estimated MSEs for annualized estimates for all injuries and for less severe injuries were attained when the annualized estimates were based on 3--6 elapsed cumulative weeks between injury and interview. The average weighted number of injuries reported per week per year was 8% lower in later weeks (weeks 6--13) than in earlier weeks (weeks 1--5) for all episodes, and 24% lower in later weeks than in earlier weeks for contusions/superficial injuries, with both differences being statistically significant. For fractures, however, the averages in the two periods were statistically similar.
  
  
  CONCLUSIONS
  The error associated with the estimated annual number of injuries was large with a three month reference period for all injuries and for less severe injuries. Limiting analysis to episodes with up to five weeks between injury and interview has statistical, intuitive, and analytic appeal for all injuries and for less severe injuries.
authors.affiliation: Office of Analysis and Epidemiology, National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, MD 20782, USA. mwarner@cdc.gov
authors.forename: M
authors.initials: M
authors.lastname: Warner
authors.forename: N
authors.initials: N
authors.lastname: Schenker
authors.forename: M A
authors.initials: MA
authors.lastname: Heinen
authors.forename: L A
authors.initials: LA
authors.lastname: Fingerhut
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004812:Epidemiologic Methods; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D011939:Mental Recall; D008875:Middle Aged; D011041:Poisoning / Q000453:epidemiology*; D012650:Self Disclosure; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D014947:Wounds and Injuries / Q000453:epidemiology*