Product of a spatial weights matrix *W* and a given variably *Y*

*Y*_{sl} = *W**Y* *y*_{sl − i} = ∑_{j}*w*_{ij}*y*_{j}

- Measure that captures the behaviour of a variable in the neighborhood of a given observation
*i*. - If
*W*is**standardized**, the spatial lag is the*average value of the variable in the neighborhood*

Common way to introduce space formally in a statistical framework

Heavily used in both ESDA and spatial regression to delineate neighborhoods. Examples:

- Moran’s I
- LISAs
- Spatial models (lag, error…)

A course on Geographic Data Science by Dani Arribas-Bel is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.