Table 2.
Scenario | Mother’s date of birth or age | Baby’s date of birth | Mother’s postal code | Baby’s sex | Probability of re‑identification* |
---|---|---|---|---|---|
S1 | Year | day, month, year | 3 character | Unchanged | 0.973 |
S2 | Year | month, year | 3 character | Unchanged | 0.677 |
S3 | Age in 5-year groups | month, year | 3 character | Unchanged | 0.327 |
S4 | Age ≤19, 20-30, 30-40, >40 | month, year | 3 character | Unchanged | 0.23 |
S5 | Age ≤19, 20-30, 30-40, >40 | month, year | 1 character | Unchanged | 0.007 |
S6 | Year | month, year | 1 character | Unchanged | 0.034 |
S7 | Age in 5-year groups | quarter, year | 3 character | Unchanged | 0.152 |
S8 | Age ≤19, 20-30, 30-40, >40 | quarter, year | 3 character | Unchanged | 0.1 |
*Probability was measured using the average re-identification risk metric defined elsewhere.7