Background In individually randomised trials we might expect interventions delivered in
groups or by care providers to result in clustering of outcomes for participants treated in the …

Analysis of the differential treatment effects across targeted subgroups and contexts is a
critical objective in many evaluations because it delineates for whom and under what …

We began preparing this special issue with a widely accepted realization: the search of
'what works' in educational contexts has been problematic in practice and in theory as well …

Abstract artially nested designs (PNDs) are common in intervention studies in psychology
and other social sciences. With this design, participants are assigned to treatment and …

Comprehensive evaluation of treatment effects is aided by considerations for moderated
effects. In educational research, the combination of natural hierarchical structures and …

Objectives The Scleroderma Patient-centered Intervention Network—Scleroderma Support
group Leader EDucation (SPIN-SSLED) Programme was designed to improve confidence …

Analyses of trials of group administered treatments require an identifier for therapy group to
account for clustering by group. All patients randomized to receive the group administered …

Purpose: Group-administered and shared facilitator treatments can induce nested data in a
treatment arm that is not present in the control arm. Failure to accommodate these partially …

Subjects in randomized controlled trials do not always comply to the treatment condition they
have been assigned to. This may cause the estimated effect of the intervention to be biased …

Intervention studies in psychology often have a partially nested design (PND): After
individuals are assigned to study arms, individuals in a treatment arm are subsequently …