The population size for each parish is based on mid-2014 estimates (30th June 2014). Remaining analysis is based on Census 2011 data and hence captures the population characteristics as they were on 27th March 2011. The socio-demographic characteristics of the population could have changed between then and the time when this website was last updated. Some areas, for example where there is a lot of newly built houses or significant student or migrant population will be more dynamic, hence changes over time may be more significant.
The data were released by ONS at the Output Area level (small areas containing about 125 households and delivered from Census data). These areas were then matched to parish areas, using 'population weighted centroids', built by ONS. This ensures fairly accurate capture of the population characterisics, however matched areas may cover patches of sparsely populated, industrial or green land outside individual parish areas.
The answers to Census questionnaire reflect respondents’ perception and it is possible that some of the answers are incorrect, due to genuine mistakes or deception. Some of the respondents could also refuse to answer some of the questions. ONS has a methodology for checking responses for internal consistency and removes inconsistent or clearly incorrect entries. This in turn means that the base population for each characteristic may be slightly different.