Purpose: To demonstrate the need for standardized definitions and data reporting for Early Hearing Detection and Intervention (EHDI) programs collecting information on newborn hearing screening and follow-up.

Method: A hypothetical birth cohort is used to show the potential effects of using non-standardized definitions and data classifications on rates of hearing screening, audiologic follow-up, and confirmed hearing loss.

Results: In a hypothetical cohort with true newborn hearing screening coverage of 92.4%, the calculated screening rate was 90.0%–96.5% depending on the measure used. Among children with documented screening results referred for audiologic follow-up, 61.0% received follow-up testing, but only 49.0% were documented to have been tested. Despite a true prevalence of hearing loss of 3.7 per 1,000 births in the cohort, only 1.5 per 1,000 children were documented to have hearing loss.

Conclusion: Ensuring that children receive recommended follow-up tests is a challenge for EHDI programs. Without complete reporting by audiology practices to EHDI programs, accurate calculation of performance measures is impossible. Lack of documentation can lead to the overstatement of “loss to follow-up.” Standardization of measures is essential for EHDI programs to evaluate how many children receive recommended services and to assess progress in achieving national EHDI goals.