Data Story: Population estimates – Why are they useful?

Solid information on population counts by region and sub-region is vital for the ongoing local planning of services, such as schools, children’s centres and transport provisions and infrastructure. Such data also comes into its own for contingency planning for, and in the event of, emergency incidents, whether natural or man-made. Such occurrences potentially require the evacuation of homes and movement of people on a temporary basis, as in the case of the flash flooding in August 2014 in parts of Cambridgeshire.

Population of Cambridgeshire

Looking at population sizes of settlements over time can show the changing demographic shape of a region, in particular the impact of new housing developments and settlements. The settlement of Cambourne in South Cambridgeshire, for example, began in the late 1990s but its rapid expansion means that it is now the twelfth largest settlement in Cambridgeshire with 9,600 residents. In 2012 it overtook Ramsey in population size and in 2013 Littleport to climb up the rankings – it is now only marginally smaller than Yaxley.

Cambridge City is overwhelmingly the largest settlement within Cambridgeshire with a population of 128 thousand (just higher than the next five largest parishes of St Neots, Wisbech, Huntingdon, March and Ely put together), thereafter there are a number of significant settlements of similar size. The Chart shows Cambridgeshire’s top 15 parishes for 2013 by population size.

Where are population estimates available?

When planning services at a local level, population numbers down to individual settlement level are fundamental; yet this type of information is not readily available. Historically the Census has been the most accurate count of population and provides an important benchmark of population numbers every ten years. In the intervening years it is much more difficult to gain an accurate assessment of population sizes by settlement. The Office for National Statistics (ONS) produces annual small area population estimates. Whilst these estimates provide a useful reference, they tend to lack local insight. Local economic and housing stock factors are significant drivers on demographic developments and these local insights need to be considered for sub regional population estimates.

Cambridgeshire County Council’s population estimates

Cambridgeshire County Council produces its own annual population estimates using a combination of administrative information sources, official government statistics and its own local knowledge. These estimates are built up from ward, parish and settlement level and aggregated to provide district and ultimately county level datasets. This means that services can be planned for, encompassing the smallest of settlements. Robust data sources, such as the electoral register and reports on housing completions, along with detailed local knowledge, are used to build the estimates. The estimates are published on the Council’s Cambridgeshire Insight website ( The reports can be accessed using the following links:

Data sources

ONS Census 2011 data – 2011 Census – ONS

ONS population estimates – Small Area Population Estimates, Mid-2013 – ONS…

Cambridgeshire Insight – Population and demographics | Cambridgeshire Insight[0]=field_tags%3A19

For further information, contact:

Anna Jones – Research Officer Cambridgeshire Research Group, Cambridgeshire County Council, SH1012, Shire Hall, Cambridge, CB3 0AP


Twitter: via @CambsInsight (