Livett Migration Model Counties

The LMM version of a UK Counties lists

County Layer (44 Counties)

Treatment of County Systems and Boundary Mismatch

The Livett Migration Model (LMM) does not rely on a single fixed county system. Instead, it operates across multiple historical and administrative frameworks in order to reflect the realities of genealogical records and population movement.

In the United Kingdom, counties exist in several overlapping forms: historic counties, administrative counties, and modern or ceremonial counties. These systems do not align consistently, and direct use of any one framework introduces distortion when analysing long-term surname distribution.

The LMM resolves this by prioritising BMD registration districts and observed clustering behaviour over administrative boundaries.

Administrative counties created during late reforms are not treated as primary analytical units within the model. These include, but are not limited to, Cleveland, Avon, and Humberside. These counties were short-lived and often combine earlier historic regions. Their use introduces discontinuity when tracing families across longer time spans.

In the LMM, these counties are not retained as independent units. Their constituent districts are reassigned to functional clusters based on underlying historic geography and migration behaviour.

Cleveland (1974-1996), for example, is not used as a county layer. Districts within this area are reassigned to Yorkshire or North East clusters depending on their historical and functional alignment.

Certain historic counties are also modified where they do not function effectively as analytical units. Middlesex is the most significant example. Although historically important, it was absorbed into Greater London in 1965.

In the LMM, Middlesex is not treated as a single unit. Its districts are disaggregated and reassigned into London sub-clusters. This reflects the fact that London operates as a complex redistribution system rather than a single geographic unit.

Some historic counties are too small to function as meaningful units within a cluster-based system. Rutland is the clearest example. In such cases, the county is not treated as a primary analytical unit and its districts are absorbed into surrounding counties and clusters.

The LMM is based on the principle that population movement follows economic, geographic, and social systems rather than administrative boundaries. Counties are therefore used as an intermediate organisational layer, while clusters represent the true functional units of migration and district-level data provides the evidential foundation.

Apparent mismatches between the LMM county layer and official county lists are expected and intentional. They arise because administrative boundaries change over time, genealogical data spans multiple boundary systems, and migration patterns do not respect administrative divisions.

By prioritising district-level evidence and cluster behaviour, the LMM produces a more accurate and stable representation of surname development than any single county framework.