Data collection instrument	Response rate ^(n/N)^		Time taken to complete median (range)ˆ
Information and consent
Adolescent	100% (45/45)		6 min 6 s (1 min 38 s to 3 hours 0 min 26 s)
Chiropractor	100% (20/20)		2 min 16 s (53 s to 53 min 36 s)
Baseline questionnaire
Adolescent	97.8% (44/45)		9m36s (3m56s to 7h46m19s)
Chiropractor	100% (45/45)		1m28s (33 s to 59m20s)
Weekly SMS, adolescent	SMS (1) NRS	SMS (2) GBRS
Week 1	97.8% (44/45)	93.3% (42/45)	–	–
Week 2	93.3% (42/45)	93.3% (42/45)	–	–
Week 3	95.6% (43/45)	93.3% (42/45)	–	–
Week 4	97.8% (44/45)	91.1% (41/45)	–	–
Week 5	93.3% (42/45)	93.3% (42/45)	–	–
Week 6	93.3% (42/45)	93.3% (42/45)	–	–
Week 7	95.6% (43/45)	95.6% (43/45)	–	–
Week 8	95.6% (43/45)	95.6% (43/45)	–	–
Week 9	93.3% (42/45)	93.3% (42/45)	–	–
Week 10	91.1% (41/45)	91.1% (41/45)	–	–
Week 11	88.9% (40/45)	88.9% (40/45)	–	–
Overall	93.5% (926/990)
Follow-up questionnaire
Adolescent	93.3% (42/45)		3 min 30 s (1 min 41 s to 19 min 41 s)
Chiropractor	100% (45/45)		1 min 14 s (13 s to 22 hours 36 min 41 s)

NRS; pain intensity via the , GBRS; pain recovery via the Global Back Rating Scale, ˆ Median (range) = complete median instrument completion time (shortest to longest completion time), h; hours, m; minutes, s; seconds.

^* (n/N) = as a percentage of responses received (n) over total responses expected (N).

GBRSGlobal Back Rating ScaleNRSNumeric Rating Scale

Table 1. Response rate and time to complete for each data collection instrument.