Evaluation of the Soundex Function for the Region VIII Infertility Prevention Project (IPP)

Background:
The soundex system in the Region VIII IPP is used for the purpose of converting last names into a quasi-identifier that cannot be converted back into the last name directly, thereby protecting confidentiality.

Objective:
To determine the effectiveness of this system, we assessed the accuracy and uniqueness of the soundex identifier with date of birth (DOB) and the ability of the unique identifiers to track the utilization of services in across clinics as compared to the gold standard the National Archives and Records Administration.

Method:
A survey was conducted with each of the eleven IPP areas to determine how the soundex program is implemented in each of the project areas. We ran a random sample of names (n=350) through the regional database soundex program and then compared the soundex code derived from the regional program to the soundex code derived from the soundex program used by the NARA. To determine the uniqueness of soundex identifiers coupled with date of birth to more accurately "identify" a person within the system, we ran cross tabs to determine how many times soundex code is correlated with the same date of birth.

Result:
Ten responses were received out of the eleven surveys sent. There are six distinct processes in which the soundex algorithm is implemented. The comparison of the soundex code derived from the regional dBase program to the NARA program found the regional dBase program was 100% specific and sensitive. When the soundex identifier is coupled with date of birth, a unique identifier is created that can identify the same person over time.

Conclusion:
Based on these results, the system is fully capable of tracking retesting for chlamydia infection.

Implications:
The ability to track recurrence of chlamydia infection and retesting for chlamydia infection can give programs important information for program planning and outreach.