Summary
Statistical geographies help you compare two areas using boundaries that official datasets understand. In England and Wales, Lower Layer Super Output Areas and Middle Layer Super Output Areas are especially useful because many public datasets can be linked to them more reliably than to informal place names.
Definition
Statistical geographies are standard geographic units used by official statistics producers to publish and compare local data. Lower Layer Super Output Areas are small areas built from groups of Output Areas and are designed to contain broadly similar population and household ranges. Middle Layer Super Output Areas are larger areas made from groups of LSOAs. For example, an LSOA may be useful for comparing small neighbourhood level crime, journey time or flood exposure signals, while an MSOA may be better for broader area comparisons where the sample size would be too small at LSOA level.