Contact day	Arm 1: Mail + telephone (standard mixed mode)	Arm 2: Paper invite + email (x2) + mail (x2)	Arm 3: Paper invite + email (x3) + mail	Arm 4: Email (x4) + telephone	Arm 5: Email (x4) + mail + telephone	Arm 6: Email (x4) + mail (x2)	Arm 7: Text + email + text + email + mail (x2)	Arm 8: Paper invite + text + email (x2) + mail	Arm 9: Paper invite (URL only) + email (x2) + mail (x2)
1	Mailed survey	Mailed invitation (containing QR code & URL)	Mailed invitation (containing QR code & URL)	Emailed link	Emailed link	Emailed link	Texted link	Mailed invitation (containing QR code & URL)	Mailed invitation (containing URL only)
2				Emailed link	Emailed link	Emailed link	Emailed link
4				Emailed link	Emailed link	Emailed link	Texted link
6		Emailed link	Emailed link	Emailed link	Emailed link	Emailed link	Emailed link	Texted link	Emailed link
8		Emailed link & mailed survey	Emailed link	Telephone attempt 1 (5 max)	Mailed survey	Mailed survey	Mailed survey	Emailed link	Emailed link & mailed survey
10			Emailed link					Emailed link
14			Mailed survey					Mailed survey
22	Telephone attempt 1 (5 max)	Mailed survey			Telephone attempt 1 (5 max)	Mailed survey	Mailed survey		Mailed survey