Response Errors in Surveys of Children's
Immunizations
Series
6, No. 8. Response Errors in Surveys of Children's Immunizations. 56 pp. (PHS)
99-1083. GPO stock number and price forthcoming View/download PDF 300 KB
Survey
of childrens immunizations often require reports by adults who may not have access
to records such as a childs shot card. This report describes research to explore
whether, in the absence of records, a) parental memory is sufficient for obtaining data of
adequate quality, and b) if performance can be improved through the use of retrieval cues
that enhance access to the relevant memories. Findings from the report concluded that
parental reports were generally poor, and that attempts to improve memory performance were
unsuccessful. To the extent possible, immunization surveys should rely on the use of
medical provider record data.
Data
Highlights:
Overall, there
was little relationship between parental reports and the childs vaccination status
according to provider records. Parent reports of overall (4-3-1-3-3) up-to-date status
revealed net overreporting (net bias of +53 percent). Accuracy for number of individual
vaccines received was significantly above chance only for MMR, and in contrast to reports
concerning the global questions, reports involving individual vaccines tended to represent
net underreports. Finally, over- reporting was observed for vaccines that the child would
never have received (smallpox, varicella, and pneumococcus).
The medical
events calendar seemed more helpful than the personal events calendar because it
encouraged respondents to draw specifically on memories of doctor visits and illnesses. In
particular, its structure was helpful in laying out the 2-year reference period clearly.
This calendar seemed to help respondents recall the months in which their children
received vaccinations, but not which vaccines were given. Overall, only the medical events
calendar appeared to be worthy of further investigation.
The use of the
calendar, show card, and variation in presentation order had no significant affects on
accuracy of reporting of either overall up-to-date status or number of individual
vaccines. Overall, attempts to improve reporting through the use of recall aids were
unsuccessful.
The only
variable found to be related to reporting accuracy was an independent measure of the
parents knowledge concerning the functions of each vaccine, parents who were about
the median level concerning such knowledge were more accurate than those who were below
the median.