Table 1 .

Probability of re-identification of anonymised data in BORN (Ontario birth registry dataset) for various combinations of quasi-identifiers

Mother’s date of birth	Baby’s date of birth	Mother’s postal code	Baby’s sex	Probability of re‑identification*
X				0.014
	X			0.005
X	X			0.88
X	X	X		1.00
X	X	X	X	1.00
X	X		X	0.91
	X	X		0.98
X		X		0.85
		X		0.19

X indicates that a variable is included in the calculation of probability.

*Probability was measured using the average re-identification risk metric defined elsewhere.⁷