Table 2.

Correspondences between occupation classifications based on ‘official’ crosswalks.

			Target classification
			7-digit CCDO-1971		5-digit ISCO-1968		6-digit US-SOC-2010		4-digit NOC-2011
		Ncodesa	NTablesb	Median (5th–95th percentile)c	N Tables β	Median (5th–95th percentile)c	N Tables b	Median (5th–95th percentile)c	N Tables b	Median (5th–95th percentile)c
Starting classification	7-digit CCDO-1971	7907			7	53 (7–239)	5	17 (2–56)	4	4 (1–10)
	5-digit ISCO-1968	1504	7	231 (20–1165)			2	3 (1–13)	2	4 (1–18)
	6-digit US-SOC-2010	840	5	68 (6–894)	2	5 (1–22)			2	1 (1–6)
	4-digit NOC-2011	500	4	34 (4–212.05)	2	8 (2–52)	2	3 (1–11.05)

^aNumber of different codes for the classification.

^bNumber of intermediate tables used between the starting and target classifications for ‘official’ crosswalks.

^cMedian and values of the 5^th and 95^th percentile of the distribution of numbers of possible codes in the target classification linked with each code in the starting classification.