Table 2 Millennium Cohort Study participant eligibility, response, and mode of response between 2001-2003 and 2014-2016 surveys, n=201,619

1

Enrolled: 77,019

Web: 42,167 (55%)

Paper: 34,852 (45%)

Eligible: 76,829 (99%)

Nonresponder:

21,812

Responder:

55,017 (72%)

Web 45,538 (83%)

Paper: 9479 (17 %)

Eligible: 76,044 (99%)

Nonresponder:

21,260

Responder:

54784 (72%)

Web: 46,303 (85%)

Paper: 8481 (15%)

Eligible: 75,419 (98%)

Nonresponder:

23,745

Responder:

51,674 (69%)

Web: 42,615 (82%)

Paper: 9059 (18%)

Eligible: 71,201 (93%)

Nonresponder:

23,707

Responder:

47,494 (67%)

Web: 39,335 (83%)

Paper: 8159 (17%)

1: 9336 (12.1)

2: 9154 (11.9)

3: 10,662 (13.8)

4: 12,978 (16.9)

5: 34,889 (45.3)

Excluded: 190 *

Excluded: 975*

Excluded: 1600 *

Excluded: 5818 *

2

Enrolled: 31,110

Web: 27,250 (88%)

Paper: 3860 (12%)

Eligible: 31,044 (99%)

Nonresponder:

13,892

Responder:

17,152 (55%)

Web: 14,357 (84%)

Paper: 2795 (16%)

Eligible: 30,842 (99%)

Nonresponder:

15,693

Responder:

15,149 (49%)

Web: 12,106 (80%)

Paper: 3043 (20%)

Eligible: 29,147 (94%)

Nonresponder:

15,926

Responder:

13,221 (45%)

Web: 10,968 (83%)

Paper: 2253 (17%)

1: 9217 (29.6)

2: 7172 (23.1)

3: 5814 (18.7)

4: 8907 (28.6)

Excluded: 66*

Excluded: 268*

Excluded: 1963*

3

Enrolled: 43,438

Web: 40,302 (93%)

Paper: 3136 (7%)

Eligible: 43,324 (99%)

Nonresponder:

21,256

Responder:

22,068 (51%)

Web: 18,174 (82%)

Paper: 3894 (18%)

Eligible: 41,023 (95%)

Nonresponder:

23,211

Responder:

17,812 (43%)

Web: 14,943 (84%)

Paper: 2869 (16%)

1: 18,061 (41.6)

2: 10,875 (25.0)

3: 14,502 (33.4)

Excluded: 114*

Excluded: 2415*

4

Enrolled: 50,052

Web: 43,781 (87%)

Paper: 6271 (13%)

Eligible: 47,636 (95%)

Nonresponder:

22,925

Responder:

24,711 (52%)

Web: 20,633 (83%)

Paper: 4078 (17%)

1: 25,341 (50.6)

2: 24,711 (49.4)

Excluded: 2416*