Coverage adjustment/estimation/Coverage Assessment and Adjustment (CAA)

Coverage adjustment is the process of combining the results of the census and information gathered via a follow up survey (the Census Coverage Survey) to make a reliable estimate of those not counted in the main census. It also accounts for bias in non-response and overcount within the population. This allows a highly precise estimate of the total resident population to be made. This approach is internationally recognised.

Confidence Intervals

A confidence interval is a measure of uncertainty around an estimate from a survey, indicating the range of values within which the true (population) measure being estimated lies with a given degree of confidence. In other words the confidence interval provides the range within which (say) 95 per cent of estimates could be expected to lie if the survey was repeated. The 95 per cent confidence interval for 2011 Census population estimate of Scotland is 5,295,000 plus or minus 23,000 people.

Comparator data

A range of data was used to help quality assure 2011 Census estimates. These data included administrative sources (such as the number of people registered with a doctor) and other official NRS products (such as the mid-year population estimates).

More information is available about the wider process for quality assurance.

Communal establishment resident

A communal establishment resident is a person whose place of usual residence is in managed residential accommodation. This means any person who was living, or expected to live in a communal establishment for six months or more. Individuals resident in a communal establishment for less than six months are included as resident at their home address.

A person normally resident at the establishment who was absent on census day is still classified as a resident of the establishment, and also counted as a visitor to the address at which they were staying on census day.

Communal Establishment

A communal establishment is an establishment providing managed residential accommodation. ‘Managed’ in this context means full-time or part-time supervision of the accommodation. Communal establishments include sheltered accommodation units, hotels, guest houses, B&Bs and inns and pubs, and all accommodation provided solely for students (during term-time).

Small communal establishments are defined as those with less than 100 bed spaces. Large communal establishments are those with 100 or more bed spaces.

Cohabiting couple household

A cohabiting couple household is a household that comprises a cohabiting couple family and no other person. This definition is used in most results from the 2011 Census.
In a small number of results a cohabiting couple household is defined as a household that contains at least one cohabiting couple, but does not contain any married or same-sex civil partnership couples. When this definition is used it is clearly indicated.

Cohabiting couple family

A cohabiting couple family consists of two people of any sex who are living together as a couple, with or without their child(ren), but who are not married or in a same-sex civil partnership. Child(ren) included in the cohabiting couple family may belong to both members of the couple or only one. Children are included in the family only if they are not themselves living with a spouse, same-sex civil partner or partner and do not have any children of their own in the household.


Two people are described as cohabiting if they are living together as a couple but are not married to each other or in a registered same-sex civil partnership together. This includes people living with a partner of the same sex. A cohabiting person might be married or in a civil partnership (with someone not resident in the household) but will not be shown as married, in a civil partnership or separated in results relating to living arrangements because cohabiting in this classification takes priority over legal marital or partnership status.


Coding, in census terms, involves allocating codes to each answer to make it easier for statisticians to analyse.


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