Immunization performance measurement in a changing immunization environment

Objective. The measurement of performance in the delivery of recommended va ccinations for children is used frequently as a marker for quality of care and as an outcome for studies of interventions to improve immunization cove rage levels. The critical element of immunization performance measurement i s the determination of immunization status. This methodologic review 1) dis cusses immunization status as a measure of quality of primary care for chil dren, 2) describes immunization status measures used in immunization interv ention studies, and 3) examines selected technical issues of immunization s tatus measurement. Methods and Topics, 1) Description of the characteristics of immunization s tatus measurements obtained by a systematic review of studies published bet ween 1980 and 1997 on interventions to raise immunization coverage, and 2) illustration of technical considerations for immunization status measuremen t using one local database and one national database of immunization histor ies. Technical issues for immunization status measurement include 1) the ne ed to use documented immunization histories rather than parental recall to determine immunization status, 2) the need to link records across providers to obtain complete records, 3) the sensitivity of immunization status to m issing immunization data, and 4) the potential of measures incorporating co mbinations of immunizations to underestimate the degree of vaccination in a population. Conclusions. Immunization performance measurement has many characteristics of a robust quality of care measure, including high acceptance by primary c are providers of routine vaccination, association of immunization status wi th the conduct of other clinical preventive services, agreed-on technical a nd programmatic standards of care, and legislative requirements for medical record documentation. However, it is not without challenges. Careful atten tion to technical issues has potential to improve immunization delivery hea lth services research.