How data is calculated for custom areas drawn on the map

In Local Insight you can create bespoke geographies by drawing on the map and then view data for those areas in the reports and dashboards. This article explains how Local Insight calculates data for those bespoke areas.

Data in Local Insight:

• All the indicators in Local Insight are published at statistical area level; Output Area (OA), Lower layer Super Output Area (LSOA) and Middle layer Super Output Area (MSOA). To see at what level an indicator is published at you can view the list of all indicators in Local Insight and filter column H, Lowest Published Geography.
• Depending on the level the data is published at Local Insight either aggregates that data up to show at higher geographies or apportions that data down to show at lower geographies.

Aggregation

The process of summing data from component areas to give a value for a larger area.

Apportioning

The process of modelling data published at higher geographies (LSOA / MSOA) to get values for smaller geographies. Read more about how apportioning and aggregation work in Local Insight.

Data for areas drawn on the map:

• In order to calculate data for the bespoke drawn on map areas, Local Insight has a methodology which identifies the underlying component standard areas. Data is then aggregated for those underlying component areas. Local Insight apportions all data down to OA level, this is the smallest component area in Local Insight. For a drawn area to work in Local Insight it must cover at least one OA area.  

How Local Insight identifies the underlying component areas:

Local Insight overlays standard geography boundaries against the drawn area boundary to check the extent to which the boundaries overlap. Boundaries are checked according to geographical hierarchy with the largest boundaries (MSOAs) overlaid first.

1. Where an MSOA falls entirely within the drawn boundary it is included.
2. Where an MSOA falls partially within a drawn boundary, the component LSOAs are overlaid against the drawn boundary.
3. Where the component LSOAs fall entirely within the drawn boundary they are included.
4. Where a drawn area cuts across a component LSOA boundary, the Output Areas within the boundary are then overlaid against the drawn area.
5. Those Output Areas that fall entirely within the drawn boundary are included.
6. Where an output area falls partially within the boundary, it is included if at least 50% of the residential postcodes within the Output Area are included.

How to see the component areas for your custom areas

The component areas which make up your custom area can be viewed for each area. To do this:

1. Click on the Areas button on the map page
2. Locate the area you are interested in
3. Click on the i icon next to the are name
4. This will open up a popup which details information about that custom areas including the component areas which are termed in Local Insight as constituent regions.