multilevel

Multilevel is an adjective used to describe systems, analyses, or designs that involve more than one level of organization or scale. The term appears in several disciplines to indicate that phenomena at one level influence or are influenced by phenomena at another level, and that methods or structures acknowledge this nested or hierarchical arrangement.

In statistics, multilevel models (also called hierarchical linear models) handle data that are nested or grouped, such as students within classrooms or patients within clinics. They extend regression by including random effects and possibly varying slopes at higher levels, allowing partial pooling of information across groups and improving estimates when group sizes vary.

In governance and organization, multilevel governance describes decision-making distributed across multiple levels, such as local, regional, national, and international authorities. This framework emphasizes interaction and coordination among levels in public policy, planning, and service delivery.

In marketing, multilevel marketing (MLM) is a distribution approach in which participants earn commissions on their sales and on the sales of their recruits. MLM schemes are distinct from illegal pyramid schemes but face ongoing regulatory scrutiny and criticism about profitability and market saturation.

In computing and optimization, multilevel methods refer to techniques that operate at different resolutions, scales, or layers, such as multilevel discretization, preconditioning, or hierarchical optimization. These methods can improve efficiency for large-scale problems.

See also: hierarchical modeling, nested data, organization theory, governance, network marketing, multi-resolution.