Here are some free listings of commonly used demographics, lifestyle and geodemographical classifications.
Table of contents
Here are some free listings of commonly used demographics, lifestyle and geodemographical classifications.
The word 'geodemographics' combines the analysis of demographic lifestyle and geography.
The term demographics is from the Greek words demos, the people, and graphos, meaning written, in the sense of representation, analysis and diagrams.
Social class definitions and geodemographics are mainly used by marketing professionals, statistical researchers and social and lifestyle commentators, but the study and theory of demographics, and the systems within it, are very helpful for anyone who has an interest in people and behaviour (US, behavior), social science, lifestyle, relationships, management and business generally.
Terms like 'ABC1' - as a definition of consumer types - are often used to describe a profile of users or target customers.
Demographical and social grade definitions enable the classification and measurement of people of different social grade and income and earnings levels, for market research, targeting, social commentary, lifestyle statistics, and statistical research and analysis.
A basic assumption, and probably a proven accepted principle within demographics, is that people living in similar 'neighbourhoods' (US, 'neighborhoods') generally exhibit similar lifestyle and spending tendencies. This enables businesses and other providers of services to adapt and 'target' their offerings and communications according to geographical areas, and/or in other ways so as to understand, communicate and deliver the most relevant offerings to the most relevant people.
Researchers and social scientists also use demographics, whose principles enable surveying and analysis of individual and group behaviour at a deep and complex level.
Much of the basic data used in demographics is derived from national census information, traditionally gathered by governments (and for some while now theoretically available to us all in the UK and most other developed nations). Demographics services organizations, like the examples here, perform a vital role in interpreting these vast amounts of national data - typically too cumbersome to be easily used in a 'raw' state - in developing user-friendly profiling and analysis systems like the ones explained here below.
Included in the explanations here are NRS, CACI ACORN and INSIGHT classifications, including the excellent free ACORN UK population percentages reports.
Demographics profiling systems on this page are:
CACI's ACORN system
NRS's 'ABC1 social grade' demographics profiling system - and
Insight Social Value Group
While this demographics guide focuses on UK consumer profiling systems, the principles of demographic profiling broadly transfer everywhere else.
I am open to suggestions to add summaries and resources from providers of overseas and international demographics profiling systems.
ACORN is a geodemographic (combining geographical and demographics analysis) classification of British social classes and is used by marketing professionals, entrepreneurs and researchers, to measure and target consumers and characteristics.
The ACORN acronym meaning is 'A Classification Of Residential Neighbourhoods'. (See other interesting business acronyms).
Here is CACI's 2013 ACORN UK Demographics Profile and User Guide.(This is a big 5.6MB pdf file.)
ACORN is a population profiling 'segmentation tool' which categorises the UK's population into demographic types.
Here is a summary (pdf) of the 2013 ACORN UK Demographics Statistics.
Acorn segments households, postcodes and neighbourhoods into 6 categories, 18 groups and 62 types. This compares with and supersedes the previous Acorn 2010 system, which comprised 5 categories, 17 groups and 56 types. (Also big file, 6.7MB)
Whether or not you use ACORN classifications, it is useful to know broadly how such a profiling method operates. The classifications also provide a thought-provoking profile of the different social groupings in Britain today - which to varying degrees is reflected across the developed and developing world. Societies everywhere are much more mixed than ever before, and they will continue to become more so.
For historical reference purposes the 2010 CACI ACORN UK Demographics Profile and User Guide (originally published October 2010) remains available here as a free pdf file. This is a big file (6.7MB). CACI's 2010 ACORN demographic profile was based on the 2001 census, which provided about 30% of the data, and ongoing research via CACI's consumer lifestyle databases, covering the UK's [then] 46 million adults and 23 million households. It is superseded by the 2013 Acorn standards.
In turn the 2010 Acorn standards superseded the 2004 CACI ACORN UK Demographics Profile and User Guide (big file - 8.5MB) which also remains available here for historical reference purposes.
CACI provide annual percentages population figures each year for each classification, although the large Demographics Profile Report and User Guide is not updated every year. When it is next updated I will endeavour to make the new edition available here, subject to agreement with CACI.
The ACORN resources, demographics classifications and percentages and reproduced here with CACI's permission, which is gratefully acknowledged.
I encourage you to visit the CACI website and Acorn microsite, which contain many other useful resources, and offer useful demographics analysis functionality free online, including a certain level of free demographics reporting by specified area, in addition to chargeable demographic reporting (by postcode, etc), based on the ACORN UK demographic classifications.
As UK society has changed in recent years, so has the ACORN profile, in its classifications structure, and in its percentage figures across the different classifications.
The percentage figures in the 2013 ACORN demographics classifications supersede previous ACORN data.
The definitions within the 2010 ACORN demographic classifications were unchanged compared to those of the 2004 report, having been revised and expanded from the earlier 2001 ACORN demographic classifications. For historical reference purposes the 2001 and 2004 definitions are shown below.
For all current considerations refer to the 2013 ACORN classifications and definitions, and/or summary of the 2013 ACORN UK Demographics Statistics.
Further information is at the ACORN section of CACI's website.
Here is a summary (pdf) of the 2013 ACORN UK Demographics Statistics - a UK profile according to the ACORN classifications. The report was provided for Businessballs by CACI and is offered free to Businessballs users, with grateful acknowledgments to CACI. This document supersedes the historical figures for earlier years.
Here is a more concise overview of Acorn's 2013 UK population profile of demographics percentages, followed by a more detailed analysis.
|Acorn Group Description||Population||%|
|1.A - Lavish Lifestyles||820,947||1.3|
|1.B - Executive Wealth||7,788,972||12.1|
|1.C - Mature Money||5,663,939||8.8|
|2.D - City Sophisticates||2,024,721||3.2|
|2.E - Career Climbers||3,579,716||5.6|
|3.F - Countryside Communities||4,160,615||6.5|
|3.G - Successful Suburbs||3,844,002||6.0|
|3.H - Steady Neighbourhoods||5,376,958||8.4|
|3.I - Comfortable Seniors||1,645,668||2.6|
|3.J - Starting Out||2,569,813||4.0|
|4.K - Student Life||1,550,112||2.4|
|4.L - Modest Means||5,078,729||7.9|
|4.M - Striving Families||5,564,601||8.7|
|4.N - Poorer Pensioners||3,128,512||4.9|
|5.O - Young Hardship||3,222,867||5.0|
|5.P - Struggling Estates||4,730,766||7.4|
|5.Q - Difficult Circumstances||2,962,375||4.6|
|6.||Not Private Households|
|6.R - Not Private Households||550,486||0.9|
The definitions and statistics in the grid below superseded the Acorn 2010 analysis.
|Acorn Type Description - 2013 (detail)||Population||%|
|1.A.3||Large house luxury||679,187||1.1|
|1.B.4||Asset rich families||1,608,936||2.5|
|1.B.5||Wealthy countryside commuters||1,498,610||2.3|
|1.B.6||Financially comfortable families||1,651,644||2.6|
|1.B.8||Prosperous suburban families||1,106,987||1.7|
|1.B.9||Well-off edge of towners||1,343,353||2.1|
|1.C.11||Settled suburbia, older people||2,044,575||3.2|
|1.C.12||Retired and empty nesters||1,400,317||2.2|
|2.D.15||Younger professionals in smaller flats||531,262||0.8|
|2.D.17||Socialising young renters||520,946||0.8|
|2.E.18||Career driven young families||1,207,369||1.9|
|2.E.19||First time buyers in small, modern homes||1,636,406||2.5|
|2.E.20||Mixed metropolitan areas||735,941||1.1|
|3.F.21||Farms and cottages||1,008,834||1.6|
|3.F.22||Larger families in rural areas||1,376,047||2.1|
|3.F.23||Owner occupiers in small towns and villages||1,775,734||2.8|
|3.G.24||Comfortably-off families in modern housing||1,578,181||2.5|
|3.G.25||Larger family homes, multi-ethnic areas||858,348||1.3|
|3.G.26||Semi-professional families, owner occupied neighbourhoods||1,407,473||2.2|
|3.H.27||Suburban semis, conventional attitudes||2,157,252||3.4|
|3.H.28||Owner occupied terraces, average income||1,261,138||2.0|
|3.H.29||Established suburbs, older families||1,958,568||3.0|
|3.I.30||Older people, neat and tidy neighbourhoods||1,426,410||2.2|
|3.I.31||Elderly singles in purpose-built accommodation||219,258||0.3|
|3.J.32||Educated families in terraces, young children||1,186,530||1.8|
|3.J.33||Smaller houses and starter homes||1,383,283||2.2|
|4.K.34||Student flats and halls of residence||610,600||1.0|
|4.K.36||Educated young people in flats and tenements||676,425||1.1|
|4.L.37||Low cost flats in suburban areas||927,746||1.4|
|4.L.38||Semi-skilled workers in traditional neighbourhoods||1,516,153||2.4|
|4.L.39||Fading owner occupied terraces||1,593,990||2.5|
|4.L.40||High occupancy terraces, many Asian families||1,040,840||1.6|
|4.M.41||Labouring semi-rural estates||1,198,799||1.9|
|4.M.42||Struggling young families in post-war terraces||1,268,393||2.0|
|4.M.43||Families in right-to-buy estates||1,575,527||2.5|
|4.M.44||Post-war estates, limited means||1,521,882||2.4|
|4.N.45||Pensioners in social housing, semis and terraces||327,712||0.5|
|4.N.46||Elderly people in social rented flats||385,469||0.6|
|4.N.47||Low income older people in smaller semis||1,558,460||2.4|
|4.N.48||Pensioners and singles in social rented flats||856,871||1.3|
|5.O.49||Young families in low cost private flats||858,863||1.3|
|5.O.50||Struggling younger people in mixed tenure||928,175||1.4|
|5.O.51||Young people in small, low cost terraces||1,435,829||2.2|
|5.P.52||Poorer families, many children, terraced housing||1,313,901||2.0|
|5.P.53||Low income terraces||763,069||1.2|
|5.P.54||Multi-ethnic, purpose-built estates||653,109||1.0|
|5.P.55||Deprived and ethnically diverse in flats||654,526||1.0|
|5.P.56||Low income large families in social rented semis||1,346,161||2.1|
|5.Q.57||Social rented flats, families and single parents||968,356||1.5|
|5.Q.58||Singles and young families, some receiving benefits||1,112,051||1.7|
|5.Q.59||Deprived areas and high-rise flats||881,968||1.4|
|6||Not Private Households|
|6.R||Not Private Households|
|6.R.60||Active communal population||120,602||0.2|
|6.R.61||Inactive communal population||429,884||0.7|
|6.R.62||Business areas without resident population||0||0.0|
Here is a summary of the 2010 ACORN UK Demographics Statistics - a UK profile according to the ACORN classifications.The report was provided for Businessballs by CACI and is offered free to Businessballs users, with grateful acknowledgments to CACI. This document supersedes the historical figures shown in the grids below, and was superseded by the Acorn 2013 classifications/statistics.
The figures in the grid below (not the definitions) have been superseded by the Acorn 2010 analysis. The figures below are therefore provided mainly for historical reference purposes.
This is the ACORN profile developed by CACI Ltd based on 2005 definitions and percentages, unchanged from the 2003-4 classifications and data.
|category||% of UK pop||group||% of UK pop||type||name||% of UK pop|
|wealthy achievers||25.1%||A||wealthy executives||8.6%|
|cat. 1||A||1||wealthy mature professionals, large houses||1.7%|
|1||A||2||wealthy working families with mortgages||1.5|
|1||A||3||villages with wealthy commuters||2.7|
|1||A||4||well-off managers with larger houses||2.6|
|1||B||5||older affluent professionals||1.8|
|1||B||7||old people, detached homes||1.9|
|1||B||8||mature couples, smaller detached homes||2.0|
|1||C||9||older families, prosperous suburbs||2.1|
|1||C||10||well-off working families with mortgages||2.3|
|1||C||11||well-off managers, detached houses||3.7|
|1||C||12||large families and houses in rural areas||0.6|
|urban prosperity||10.7||D||prosperous professionals||2.2|
|2||D||13||well-off older professionals, larger houses and converted flats||0.9|
|2||D||14||older professionals in suburban houses and apartments||1.4|
|2||E||15||affluent urban professionals, flats||1.1|
|2||E||16||prosperous young professionals, flats||0.9|
|2||E||17||young educated workers, flats||0.6|
|2||E||18||multi-ethnic young, converted flats||1.1|
|2||E||19||suburban privately renting professionals||0.9|
|2||F||20||student flats and cosmopolitan sharers||0.6|
|2||F||21||singles and sharers, multi-ethnic areas||1.6|
|2||F||22||low income singles||1.2|
|comfortably off||26.6||G||starting out||2.5|
|3||G||24||young couples, flats and terraces||1.0|
|3||G||25||white collar singles/sharers, terraces||1.4|
|3||H||26||younger white collar couples with mortgages||1.9|
|3||H||27||middle-income, home owning areas||2.9|
|3||H||28||working families with mortgages||2.6|
|3||H||29||mature families in suburban semis||3.3|
|3||H||30||established home-owning workers||3.6|
|3||H||31||home-owning asian family areas||1.1|
|3||I||32||retired home owners||0.9|
|3||I||33||middle-income, older couples||3.0|
|3||I||34||lower incomes, older people, semis||2.1|
|3||J||35||elderly singles, purpose-built flats||0.7|
|3||J||36||older people, flats||1.9|
|modest means||14.5||K||asian communities||1.6|
|4||K||37||crowded asian terraces||0.5|
|4||K||38||low income asian families||1.1|
|4||L||post industrial families||4.8|
|4||L||39||skilled older families, terraces||2.8|
|4||L||40||young working families||2.1|
|4||M||blue collar roots||8.0|
|4||M||41||skilled workers, semis and terraces||3.3|
|4||M||42||home-owning families, terraces||2.8|
|4||M||43||older people, rented terraces||1.8|
|hard pressed||22.4||N||struggling families||14.1|
|5||N||44||low income larger families, semis||3.3|
|5||N||45||low income, older people, smaller semis||3.0|
|5||N||46||low income, routine jobs, terraces and flats||1.4|
|5||N||47||low income families, terraced estates||2.6|
|5||N||48||families and single parents, semis and terraces||2.1|
|5||N||49||large families and single parents, many children||1.7|
|5||O||50||single elderly people, council flats||1.8|
|5||O||51||single parents and pensioners, council terraces||1.9|
|5||O||52||families and single parents, council flats||0.8|
|5||P||high rise hardship||1.6|
|5||P||53||old people, many high rise flats||0.8|
|5||P||54||singles and single parents, high rise estates||0.9|
|5||Q||inner city adversity||2.1|
|5||Q||55||multi-ethnic purpose-built estates||1.1|
|5||Q||56||multi-ethnic, crowded flats||1.1|
|U||unclassified||0.3||57||mainly communal population||0.3|
This is the Acorn profile developed by CACI Ltd based on 2001 definitions. It was been superseded by the later demographics profiles and percentages shown above. The current ACORN percentage figures are contained in the 2013 analysis, so these 2001 profiles, the 2003-5 definitions/percentages above, and 2010 classifications, are provided for historical reference.
|acorn 'types'||acorn 'groups'|
|A - thriving |
1.1 wealthy suburbs
1.2 villages with wealthy commuters
1.3 mature affluent home-owning areas
1.4 affluent suburbs, older families
1.5 mature well off suburbs
2.6 agricultural villages, home-based workers
2.7 holiday retreats, older people, home-based workers
2.8 home owning areas, well-off older residents
3.9 private flats, elderly people
|1 - wealthy achievers, suburban areas |
2 - affluent greys, rural communities
3 - prosperous pensioners, retirement areas
|B - expanding |
4.10 affluent working families with mortgages
4.11 affluent working couples with mortgages, new homes
4.12 transient workforces, living at their place of work
5.13 home owning family areas
5.14 home owning family areas, older children
5.15 families with mortgages, younger children
|4 - affluent executives, family areas |
5 - well-off workers, family areas
|C - rising |
6.16 well-off town and city areas
6.17 flats and mortgages, singles and young working couples
6.18 furnished flats and bedsits, younger single people
7.19 apartments, young professional singles and couples
7.20 gentrified multi-ethnic areas
8.21 prosperous enclaves, highly qualified executives
8.22 academic centres, students and young professionals
8.23 affluent city centre areas, tenements and flats
8.24 partly gentrified multi-ethnic areas
8.25 converted flats and bedsits, single people
|6 - affluent urbanites, town and city areas |
7 - prosperous professionals, metropolitan areas
8 - better-off executives, inner city areas
|D - settling |
9.26 mature established home owning areas
9.27 rural areas, mixed occupations
9.28 established home owning areas
9.29 home owning areas, council tenants, retired couples
10.30 established home owning areas, skilled workers
10.31 home owners on older properties, younger workers
10.32 home owning areas with skilled workers
|9 - comfortable middle agers, mature home owning areas |
10 - skilled workers, home owning areas
|E - aspiring |
11.33 council areas, some new home owners
11.34 mature home owning areas, skilled workers
11.35 low rise estates, older workers, new home owners
12.36 home owning multi-ethnic areas, young families
12.37 multi-occupied town centres, mixed occupations
12.38 multi-ethnic areas, while collar workers
|11 - new home owners, mature communities |
12 - while collar workers, better-off multi-ethnic areas
|F - striving |
13.39 home owners, small council flats, single pensioners
13.40 council areas, older people, health problems
14.41 better-off council areas, new home owners
14.42 council areas, young families, some new home owners
14.43 council areas, young families, many lone parents
14.44 multi-occupied terraces, multi-ethnic areas
14.45 low rise council housing, less well-off families
14.46 council areas, residents with health problems
15.47 estates with high unemployment
15.48 council flats, elderly people, health problems
15.49 council flats, very high unemployment, singles
16.50 council areas, high unemployment, lone parents
16.51 council flats, greatest hardship, many lone parents
17.52 multi-ethnic areas, large families, overcrowding
17.53 multi-ethnic estates, severe unemployment, lone parents
17.54 multi-ethnic areas, high unemployment, overcrowding
|13 - older people, less prosperous areas |
14 - council estate residents, better-off homes
15 - council estate residents, high unemployment
16 - council estate residents, greatest hardship
17 - people in multi-ethnic low income areas
The Acorn classifications (initially in 2003) also acknowledge an 'unclassified' section of British society, although no definitions are attached to it. For the record, Acorn projected in 2002 some 0.3% of the British population would fall under the 'unclassified' heading.
The ACORN resources, demographics classifications, figures and percentages and reproduced here with CACI's permission, which is gratefully acknowledged.
For all current considerations refer to the 2013 ACORN classifications and definitions. Here is a summary (pdf) of the 2013 ACORN UK Demographics Statistics.
I encourage you to visit the CACI website, and Acorn microsite, which contain many other useful resources, and demographics analysis functionality free online, including a certain level of free demographics analysis and reporting by specified catchment area, in addition to chargeable reports, based on the ACORN UK demographics system.
NRS stands for National Readership Survey (NRS Ltd).
The NRS 'ABC1' demographics profiling system - often called 'social grade definitions' - is well established and widely used.
Many people know and refer to the system simply as 'ABC1' or 'ABC' and may not necessarily understand that NRS developed and operate the scheme.
NRS is a not-for-profit company which is funded by the UK Institute of Practitioners in Advertising (IPA), Newspaper Publishers Association (NPA), and Periodical Publishers Association (PPA).
The NRS social grade definitions have been in use for decades, mainly for audience profiling and targeting by the media, publishing and advertising sectors, and have become established as a generic reference series for classifying and describing social classes, especially for consumer targeting and consumer market research.
See below for the NRS estimates of uk population by social grade Jan-Dec 2005, and for Jan-Dec 2004.
More up-to-date figures will be offered here when/if I can agree to their provision.
|social grade||social status||occupation|
|A||upper middle class||higher managerial, administrative or professional|
|B||middle class||intermediate managerial, administrative or professional|
|C1||lower middle class||supervisory or clerical, junior managerial, administrative or professional|
|C2||skilled working class||skilled manual workers|
|D||working class||semi and unskilled manual workers|
|E||those at lowest level of subsistence||state pensioners or widows (no other earner), casual or lowest grade workers|
|All UK Adults (15+)||Men||Women|
|Social Grade A||Upper Middle Class - Higher managerial, administrative or professional||Estimated 000s||1,932||1,032||900|
|Social Grade B||Middle Class - Intermediate managerial, administrative or professional||Estimated 000s||10,573||5,404||5,169|
|Social Grade C1||Lower Middle Class - Supervisory or clerical and junior managerial, administrative or professional||Estimated 000s||13,982||6,400||7,581|
|Social Grade C2||Skilled Working Class - Skilled manual workers||Estimated 000s||9,964||5,395||4,570|
|Social Grade D||Working Class - Semi and unskilled manual workers||Estimated 000s||7,819||3,712||4,107|
|Social Grade E||Those at the lowest levels of subsistence - Entirely dependent on state for long-term income||Estimated 000s||3,916||1,435||2,481|
Source: National Readership Survey, January-December 2006. With acknowledgments to NRS Ltd. Reproduced with permission. Not to be sold or published.
|All adults (15+)||Men||Women|
|Social Grade A||Population 000s||1,818||943||875|
|Social Grade B||Population 000s||10,552||5,336||5,216|
|Social Grade C1||Population 000s||13,800||6,341||7,459|
|Social Grade C2||Population 000s||9,844||5,312||4,532|
|Social Grade D||Population 000s||7,747||3,762||3,985|
|Social Grade E||Population 000s||4,009||1,455||2,554|
Source: National Readership Survey, January-December 2005. With acknowledgments to NRS Ltd. Reproduced with permission. Not to be sold or published.
|All Adults (15+)||Men||Women|
|Social Grade A||Population 000s||1,594||875||719|
|Social Grade B||Population 000s||10,189||5,182||5,006|
|Social Grade C1||Population 000s||13,757||6,304||7,453|
|Social Grade C2||Population 000s||9,924||5,349||4,575|
|Social Grade D||Population 000s||7,636||3,655||3,981|
|Social Grade E||Population 000s||4,166||1,496||2,670|
Source: National Readership Survey, January-December 2004. With acknowledgments to NRS Ltd. Reproduced with permission. Not to be sold or published.
NRS (National Readership Survey Ltd) is a separate organization specilaising in demographic information. NRS use the following summary headings as an alternative way of classifying lifestyle types in the UK. Percentage figures for the distribution of these types are available from various sources.
|A - affluent achievers|
|B - thriving greys|
|C - settled suburbans|
|D - nest builders|
|E - urban ventures|
|F - country life|
|G - senior citizens|
|H - producers|
|I - hard-pressed families|
|J - have-nots|
|K - unclassifiable|
The insight Value Group Ltd carried out a vast study of UK social values and change, and upon its findings established this social value scale. It draws heavily from Maslow's Hierarchy of Needs. This is the Insight Value Group scale, which claims to be an accurate representation of the groups that exist in the UK today.
|social value group||characteristics|
|self actualizers||focused on people and relationships, individualistic and creative, enthusiastically exploring change, 'in a framework of non-prescriptive consideration for others'|
|innovators||self-confident risk-takers, seeking new and different things, setting their own targets to achieve|
|esteem seekers||acquisitive and materialistic, aspiring to what they see are symbols of success, including things and experiences|
|strivers||attaching importance to image and status, as a means of enabling acceptance by their peer group, at the same time holding onto traditional values|
|contented conformers||wanting to be 'normal', so follow the herd, accepting of their circumstances, they are contented and comfortable in the security of their own making|
|traditionalists||averse to risk, guided by traditional behaviours and values, quiet and reserved, hanging back and blending in with the crowd|
|disconnected||detached and resentful, embittered and apathetic, tending to live in the 'ever-present now'|
The NRS ABC1 (etc) scale is not a direct correlation with earnings. Neither the CACI nor the NRS demographics and social grades classifications correlates precisely with earnings, so care needs to be taken when inferring pay or earnings levels from social grade classifications or categories.
As a guide however here are my own best estimated pay bands without overlap (which is more helpful for broad brush analysis) for the NRS ABC1 (etc) social grades. In reality there would be overlap, for instance, some C2's earn £50k or more, for example self-employed plumbers; some C1's earn £100k, for example top sales-people; some B's earn £100k, for example top performing middle managers. Which all goes to show that this scale is actually quite a dated framework. Society has changed a lot since it was created.
These broad guide figures were originally based on 2004 levels, but in light of economic contraction and recession since then are probably still reasonably reliable.
NRS grade and annual earnings (my own estimate - if you have any other suggestions let me know.)
- A - £50k and over
- B - £35-50k
- C1 - £25-35k
- C2 - £15-25k
- D - £7-15k
- E - £5-7k
Social grade systems ACORN and Super Profiles are obviously a lot more subtle, and so probably correlate better to earnings.
If you are surveying or using questionnaires to research demographics and pay levels, adjust your survey questions to indicate precisely what social grading and earnings levels information you want to measure.