Timeline of the Let’s Play programme and data collection
| Time points | Study period | |||||||||||||
| Enrolment | Pre-wait baseline | Baseline | Programme (9 weeks) | Post (immediately post-programme) | Follow-up (6 months post-programme) | |||||||||
| W12 | W0 | W1 | W2 | W3 | W4 | W5 | W6 | W7 | W8 | W9 | W9/10 | W33/34 | ||
| Study procedures | ||||||||||||||
| Eligibility screening | X | |||||||||||||
| Informed consent | X | |||||||||||||
| Randomisation | X | |||||||||||||
| Let’s Play programme | ||||||||||||||
| Group workshop | X | X | X | |||||||||||
| Home visit | X | X | X | X | X | |||||||||
| Group celebration | X | |||||||||||||
| Outcome data collection | ||||||||||||||
| Caregiver-child interaction video (10 min) | C | X | X | X | ||||||||||
| Child engagement | C | X | X | X | ||||||||||
| Child language (SALT-NZAU) | C | X | X | X | ||||||||||
| Caregiver implementation of Let’s Play techniques | C | X | X | X | ||||||||||
| IOA | C | X | X | X | ||||||||||
| PSI-4-SF (15 min) | C | X | X | X | ||||||||||
| DASS-21 (10 min) | C | X | X | X | ||||||||||
| PSOC (10 min) | C | X | X | X | ||||||||||
| SRS-2 (20 min) | C | X | X | X | ||||||||||
| PedsQL (5 min) | C | X | X | X | ||||||||||
| SDQ (10 min) | C | X | X | X | ||||||||||
| Caregiver log of Let’s Play techniques (10 min weekly) | X | X | X | X | X | X | X | X | X | X | X | |||
| Caregiver log of professional support services accessed by caregiver and child (10 min weekly) | C | X | X | X | X | X | X | X | X | X | X | X | ||
| Therapist procedural integrity | X | X | X | X | X | X | ||||||||
| TARF-R (10 min) | X | |||||||||||||
| Post-programme caregiver interview (30 min) | X | |||||||||||||
Adapted from the standard protocol items: Recommendations for Interventional Trials (SPIRIT) template.57 58
C, waitlist controls only; DASS-21, Depression, Anxiety, and Stress Scale-21; IOA, interobserver agreement; PedsQL, Pediatric Quality of Life Inventory Generic Core Scales; PSI-4-SF, Parenting Stress Index – Fourth Edition, Short Form; PSOC, Parenting Sense of Competence Scale; SALT-NZAU, Systematic Analysis of Language Transcripts, New Zealand/Australia; SDQ, Strengths and Difficulties Questionnaire; SRS-2, Social Responsiveness Scale Preschool Form, Second Edition; TARF-R, Treatment Acceptability Rating Form-Revised; X, all participants.