Limitations
RECRUITMENT
One of the limitations of the reported study relates to technical issues that were encountered with the smartphone app that was used for daily practice. During the first few weeks of the first intervention phase, in 25.42% (412/1621) of cases, a stable internet connection could not be established at the first attempt between dyadic partners in the socioemotional training. This might have negatively affected both motivation for and attitude toward daily practice of the Affect Dyad and, thus, caused the higher dropout rate in the socioemotional group (24/95, 25%) than in the mindfulness-based group (16/97, 16%). However, on average, compliance in form of performed daily practice was higher in both socioemotional intervention groups (socioemotional: 88.79%, SD 8.15%; waitlist socioemotional: 90.19%, SD 7.24%) than in the mindfulness-based training (86.4%, SD 14.53%; Despite sample recruitment in accordance with a priori power and sample size calculations, there was a high rate of participant dropout as early as between study onboarding and preintervention assessment (a total of 32/285, 11.2%). As the recruited sample was naive to contemplative practice (note that previous experience was an exclusion criterion), they might have reconsidered participation once introduced to the practice content and requirements of daily training. However, this rather heterogeneous community sample of a COVID-19 mental health study is also an asset with regard to the representativeness of the population. The findings are promising that the 2 app-delivered trainings can indeed be used to boost empathy and compassion in the general population.