TABLE 1.
Linkage statistics by final link status, 2012–2017
| Total | Number of patients | Percent |
|---|---|---|
| Linked—exact match on five identifiers | 91,028 | 62.90 |
| Linked—partial match (less than five identifiers) | 45,585 | 31.50 |
| Not linked—partial match (less than five identifiers) | 8114 | 5.61 |
| Total | 144,727 | 100 |
| A. Linked—partial match (N = 45,585) | ||
| DOB, first name, last name, sex, missing SSN | 32,609 | 71.53 |
| DOB, first name, last name, sex, partial SSN | 4603 | 10.10 |
| SSN complete or partial only | 5882 | 12.90 |
| DOB, first name, last name only | 398 | 0.87 |
| Other combinations | 2093 | 4.59 |
| Total | 45,585 | 100 |
| B. Not linked—partial match (N = 8114) | ||
| DOB complete only | 3300 | 40.67 |
| First name, sex only | 2442 | 30.10 |
| Last name only | 657 | 8.10 |
| Last name, sex only | 635 | 7.83 |
| SSN partial only | 507 | 6.25 |
| Other | 573 | 7.07 |
| Total | 8114 | 100 |
Note: Partial SSN refers to SSN with less than nine digits. Partial match means that individuals were potential matches in less than five data fields. Panel A shows the most common combinations that resulted in linkages after review even though they were not perfect matches. Panel B shows the most common reasons potential matches were not linked.
Abbreviations: DOB, date of birth; SSN, social security number.