District Hospital Trauma Mental Health Screening Interpreter Language Concordance and Post-Traumatic Stress Disorder Assessment Completion Among Mozambican Survivors: A Target-Trial Emulation of Language Broker Exposure Windows

Mozambican district hospitals serve linguistically heterogeneous trauma populations, yet the timing and modality of interpreter-mediated screening remain unstandardised. The framework specifies a before-after-control-impact design in which eight, sixteen, twenty-four or thirty-two district hospital clusters are randomised to a concordance-promoting screening protocol or to usual care, with assessment completion measured before and after implementation. Operating characteristics were characterised under a declared variance structure with a between-cluster standard deviation of 6.0, a residual standard deviation of 4.5 and an intraclass correlation of 0.64, across 2000 replications per design cell. Power to detect effects of 3, 5 and 8 percentage points was estimated for each cluster count, and the minimum detectable effect at 80% power was derived. The design requires 54 clusters to detect a 5 percentage point difference at 80% power. The framework clarifies the conditions under which language broker exposure windows can be estimated credibly and identifies the cluster counts at which district hospital evaluations become informative. It provides a methodological basis for interpreting language concordance as a modifiable determinant of trauma mental health assessment completion in Mozambique.