2.2.3. Intervention integrity
All touch interventions were provided for 15 consecutive days (7–21 days after birth), 15 min each in the morning and afternoon (9–11 a.m. and 3–5 p.m.). In our study, touch interventions were classified into the categories Yakson and GHT. Four TRNs with more than 3 years of NICU experience participated in this study; two nurses were responsible for Yakson and the other two for GHT. The first author demonstrated the Yakson protocol to the two Yakson TRNs. The TRNs then performed the Yakson protocol back to the researcher three times to ensure the integrity of the intervention. To ensure the integrity of the GHT intervention, the above GHT protocol was demonstrated to the two GHT TRNs. To avoid a possible interruption of their work, the TRNs provided Yakson or GHT to the preterm infants while they were off duty. The nurses who were responsible for one intervention were not allowed to administer the other intervention. Thus, one nurse was not permitted to administer two interventions.