Inklusionskriterium

Inklusionskriterium, or inclusion criterion, is a predefined characteristic or condition that individuals or data items must have to be part of a study, analysis, or review. Inclusion criteria help define the target population and ensure that the study questions are answerable by the data collected. They are typically specified before data collection begins and are reported in study protocols and publications.

In practice, inclusion criteria specify factors such as age range, diagnostic status, language proficiency, geographic location, prior treatments, or specific baseline measurements. They are often complemented by exclusion criteria, which identify factors that would disqualify a potential participant even if they meet the inclusion criteria. Together, inclusion and exclusion criteria delineate the study sample and aim to balance safety, feasibility, and validity.

In clinical trials, inclusion criteria ensure that participants share relevant clinical features so that the intervention’s effects can be meaningfully assessed. In observational studies and systematic reviews, they help ensure comparability across data sources and reduce heterogeneity. Criteria should be clearly justified, empirically grounded when possible, and kept as precise as necessary to avoid ambiguity.

Potential challenges include overly narrow criteria that limit generalizability, or overly broad criteria that introduce heterogeneity and affect statistical power. Transparent reporting of inclusion criteria is essential for reproducibility and for interpreting the applicability of findings, including in guidelines and meta-analyses.