| Help Page |
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Contents
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What Does This Package Do?
What Is Special About This Package?
Can Anyone Use It?
How Do I Use The Package?
What Else Can I Do With The Package?
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A Step By Step Guide To Getting Your Census DataGetting your data starts with the Selection Page, which looks like this: 
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Choosing WHEN (the years you want your data to cover)The dates for which
data are provided are controlled through the 'Search by date panel'
on the selection page. To select the years which
you would like your data to cover click on You can choose from 1 up to 4 years for which your data will be provided. To include data from the 1971 census, click in the box to the left of 1971. To include data from the 1981 census, click in the box to the left of 1981 To include data from the 1991 census, click in the box to the left of 1991 To include data from the 1991 census which have been adjusted to take account of the people missed by the census that year, click in the box to the left of the 1991 corrected. If you want to reset
your choices at anytime, click on When you have made
your choice, click on |
Choosing WHERE (the areal units which you want your data to cover)The package will provide the census data you want for areal units whose definition has been kept constant across all three censuses (1971, 1981 and 1991). This means that you can compare areas from census to census, safe in the knowledge that the definition of those areas has not changed. When you extract your census data, you can specify the type of areal units you would like the data to describe but you will always get data for the whole country. Thus, if you choose small areal units like wards, you will have lots of units to work with, if you choose large areas such as regions, you will have comparatively fewer units. The package will always give you data for the whole of Britain, so if you are only interested in census data for one part of it, you will need to separate out those areas you need from the data the package gives you. Using the labeling function can help here. There are many different
sets of boundaries for which data can be provided and you can select one
set by clicking the A variety of different
boundary sets is available within each of these headings. By selecting
one heading (click on the circle to the left of the heading text) and
then clicking Within the package you can click on the name of any boundary set and see a brief technical description of it. The table below shows you the choice of boundary sets, the headings under which you will find them and how your data will be provided for each option. To choose a boundary
set, click in the circle to the left of its name and then click on You can only choose ONE boundary set at a time. The number of values listed in the What You Get column of this table describes how many values you will get for each variable you ask for, for each year. So, if you choose to get 2 variables, for 2 years, at 'Regions 1981' level, you will receive 40 values: 2 for each year, for each of the 10 Standard Regions. |
Available Boundary Sets (click here to jump to the end of the table)
* The period 1965 - 1975 was one of great change in administrative geography and both of these aggregations list areas which apparently contain 0 people. The 1961 units include and list London boroughs of that era (the pre-1965 boroughs) but because this is an aggregated geography no data is assigned to them. Instead, their population is assigned to a single unit - number 161, "London A.C". The 1971 units list areas which were 'abolished' and which therefore contain 0 people, but also includes those which were 'created' in their place.
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Choosing WHAT(the topics you want to know about)The package offers a variety of variables which are compatible across all three censuses. This means that the definition of each variable is broadly the same for the 1971, 1981 and 1991 censuses allowing you to compare the counts. The variables have been grouped together under these broad headings: Demography To select the variables
you want, click on The table below lists the variables available and the headings under which you can find them. Where appropriate, it also shows the definitions of each variable to give you an idea of how compatible the variables are from census to census. Click here to jump to the end of the table and continue reading the help file.
You can see more information about the variables by clicking on their names in the package itself. This brings up a subject definition table similar to that above but which includes information about the precise definitions and codes for the variables which may be useful for expert users. Within the table you may see a ... and placing a mouse pointer over that symbol will reveal the entire variable definition in terms of it's cell codes, which may have been truncated to save space. To choose a variable, click in the box to
the left of its name. You may choose as many variables from within a heading
as you like. When you have finished selecting variables from the list
click |
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Saving Your Selections For Reuse You can save your selections at any time. Why would you want to do this? Perhaps you need a coffee and want to come back to your selections later on, or perhaps you have a particular set of core variables which you want to extract several times. No matter which page you are on within the package, you can save your selections by choosing "Save As" from the File menu of your browser. Choose the "save as type > Webpage, HTML Only" option if using Explorer or the "save as type > HTML files" option if using Netscape. Your browser will save a file on your computer which contains all the information about your selections. To being reusing the saved selections, simply open the saved file in your web browser. You will find yourself back at the same page, with the same set of selections as when you choose to save. You may now continue to make selections or extractions as if you had never been away. There are 2 important things to note with the saving function.
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Before You Extract The Data: Labels and Code NumbersOnce you have chosen
WHAT, WHERE and WHEN
you want the data cover, consider which output options you would like
to select. On the selection page, under 'output options' you may choose
to 'Show names' and / or 'Show numbers'. Check the 'Show names' box AND
CLICK For example, if you do not check the show names box when asking for the Total Persons in 1991, by Country you would get these data: 0 47023155 2833056 4999550 If you do check the 'Show names' box you would get this: "England",47023155 "Wales",2833056 "Scotland",4999550 Likewise, checking the 'Show numbers' box would add the code numbers assigned to each areal unit, in this case: 1,"England",47023155 2,"Wales",2833056 3,"Scotland",4999550 This option can be extremely useful if you wish to use your data to draw maps since it provides a unique code number for data which refer to the same areal unit.
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Extracting Your Data We recommend that you do not close your web browser until you have saved the data file, opened it on your PC and checked that you understand exactly which data you have downloaded (you will see why in a moment). Click here if you see any error messages, rather than data or dialogue boxes telling you that you are about to save the data. The way in which you can save your data will depend on which browser you are using, and how your internet access is configured. We will therefore cover both possible routes to saving: Either
Or
Whatever route you took, once the data file is saved on your PC you can open it with any package that will read a comma separated values, (also called a .csv) file. Most spreadsheet packages such as Excel or Lotus 1,2,3 will happily read these files. "Index","Name","50","380" The text above is an example of the kind of output you will see. To generate this output we asked for the Total Persons count, and the Total Persons aged 16 and over count (what) for 1981 (when), with Countries of Britain as the areal units (where). We also asked to add labels and names. How does the output relate to the selections we made? The top line shows the order in which the data we asked for has been presented. "Index", "Name", "50", "380" tells us that on each line of data we have the label first, then the areal unit name, then the census data which correspond to the Total Persons count and then the data which correspond to the Total persons 16 and over count. In this example are able to tell that "50" corresponds to the Total Persons count by looking at the area headed 'Selected Cells' on the Execute page of the package (this is the reason for not closing that page until you're sure you know what data you have downloaded. The code for each item of census data is given, just to the left of its name). You might want to edit the file you have downloaded to change these codes into meaningful labels. The line labeled 'Total Outside Zones' tells you how many people or households the census package has data for, but which have been excluded from the areal units listed. In this example that total is 0 but in some cases there may be a few people or households counted in this line. These are often people counted on ships around the world on census night, or in areas which we have been unable to match into the set of areal units you have chosen. The numbers are almost always very small. That's it! Now you have your data. It's up to you what you do with them. Have fun. Problems Getting The DataThe most likely reason for seeing an Error Executing The Census Programme message is that you do not have permission to access the data you have selected. See the registration information for more details about this. |
Using The Calculator Page
To use the calculator
function, click You will see a page which looks something like this (though yours may have different variables and areas selected).
The calculation is controlled using the part of the page shown below: : Within the box headed 'Select a cell', each of the variables you have chosen to use is displayed, referred to by its code. For example, 1t2 refers to the Total Persons count for 1991. The page allows you to build a simple mathematical expression with these variables and the + and - mathematical operators. To build an expression, first select one of the variables by clicking on its code within the Select a cell box. It will highlight, as shown in this example: . Next click on the
Your version may well have brackets around the variable definition. This
is to help you identify which of the cell definitions belong together
to define a 'variable'. To
derive a new variable from this one, choose another from the 'Select a
cell' box and click either You can also include
your variables in the extracted data, without changing them by calculation
in anyway (for example, to insure you extract a value to act as denominator
in a proportional change calculation). To do this, first clear the expression
by clicking When you are happy
that you have included all the variables (original and derived) in the
extraction, click
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Using The Package In Expert ModeIf you have been using the package in easy mode, it may have become apparent that the interface is simply assembling a line command from the choices made by the user. You can see how the line command grows by watching what gets added to the 'Command line for expert users' box on the selection page as you make your choices. Expert user mode involves running the package by typing in a command line yourself, rather than letting the package build it for you.
How To Use The Command LineThe easy mode interface works by building a command line which is then passed to an extraction program. You may invoke the extraction program directly from the command line by typing a sentence conforming to the following syntax: census <areal_units_request> <variables_specification> <options> The program will return an error message if the command is not valid. Areal Units:The program only accepts <areal_units_requests> as standardized six character abbreviations from the following list of areal units. Subsets of these cannot be specified - you get data for every unit. The table below provides the code you need to provide for each of the possible sets of areal units.
Variables and YearsThe choice of census data count and the year from which it is drawn is made within the same piece of syntax. All 1991,1981 and 1971 census cells can be accessed, as can any set of additions or subtractions of these. There are no restrictions to mixing cells from different sections of a census or different censuses (although an arbitrary limit of a thousand cells has been set for any one run). You may find it useful to refer to the subject definition table to see how cells have been referred to when defining variables offered in easy mode access. It is also worth noting that different sections of cells apply to different parts of Britain - outside those areas their values are set to zero, as are values for restricted ward's cells. Data from 1991: The 1991 census data consists of all SAS and the three 'header' variables. Cell 2 from Table 1 is referenced as '2t1'. The standard ONS tables are used although in every case where there is an alternative table layout for Scotland, that is the one used (i.e. the English and Welsh data have been rearranged to fit within the Scottish table layout). The three header variables, unadjusted household, resident and population counts are referenced as 1t0, 2t0, 3t0 respectively. To help you identify cell and table references we have provided the entire 1991 SAS table layouts, which give the cell and table numbers of all available counts. Click here to see them. Data from 1991, adjusted for census undercount: The database contains data which have been adjusted to compensate for the 1991 census undercount and these can be accessed from the command line as though they were a different census in their own right. They are structured in exactly the same way as the 1991 census data (see above, and here for the table layouts), but are referred to using a capital T, rather than lower case t in the command line. For example 2t1 is cell 2 from table 1 in the standard 1991 census data, whereas 2T1 is cell 2 from table 1 in the corrected 1991 census data. Data from 1981: The 1981 census data consists of 5517 cells corresponding to the numbers given in the standard OPCS tables and one addition cell (5518) which contains the number of hectares which comprise the areal unit. To help you identify cell and table references we have provided the entire 1981 SAS table layouts, which give the cell and table numbers of all available counts. Click here to see them. The geographical bounds outside of which the specified cell values will be set to zero are as follows: cells 1 - 2597 : 100% 1981 census, all parts of Britain cells 2598 - 3050 : 100% 1981 census, England and Wales only cells 3051 - 3098 : 100% 1981 census, for Wales only cells 3099 - 4222 : 100% 1981 census, for Scotland only cells 4223 - 5517 : 10% 1981 census, all parts of Britain cell 5518 : hectares, England and Wales only Data from 1971: The standard OPCS tables used four separate numbering systems for the different sections of the 1971 census which have been incorporated here to ease use. To differentiate these cells from those of 1981 in the variable specification they should be postfixed by one of the letters 'P', 'H', 'p' or 'h' according to the table below: P 100% 1971 Population Census (Tables 1-14) Cells 32 - 502 H 100% 1971 Household Census (Tables 15-21) Cells 32 - 480 p 10% 1971 Census (Record 1 : Tables 22-23) Cells 32 - 399 h 10% 1971 Census (Record 2 : Tables 24-28) Cells 32 - 314 Internally these cells are simply referenced as 5519 - 7089 and tacked on the end of the 1981 data. A more import consideration with the 1971 variables is the handling of the 48 cells which were stored as ratios on the original tapes. These had to be converted into counts to allow simple aggregation. The exact transformations which were performed on these cells is given in an appendix. The cells effected are (inclusively) 471P to 493P and 53H to 77H. To help you identify cell and table references we have provided the entire 1971 SAS table layouts, which give the cell and table numbers of all available counts. Click here to see them. Showing names and unit labels: To include the areal unit names in the output, append -n to the end of the command line syntax. To include the areal unit code identifier, append -i to the syntax. To include both, append -in An Example Syntaxcensus Brit_n 36P+38P,50,1t2,1T2 -n In this example the package has been asked to extract data for the whole of Britain (Brit_n), a total persons count for 1971 (cells 36P+38P), total persons for 1981 (cell 50), total persons from the standard 1991 census data (1t2) and total persons from the 1991 census data adjusted for undercount (1T2). The package has also been asked to include the areal unit name (-n). The subject definition table can be accessed from wherever a variable name appears in the package interface and is underlined to indicate a hyperlink. The easiest and most obvious link is seen on the selection page under the Current Subject(s) heading. The default example is Total Persons. Clicking on a variable name will open the subject definition table in a new window, at the place within the table where information about that variable lies. The table reveals the cell references from each census which we have used to define the variables available for selection within easy mode. Users wishing to write their own line commands may find this a useful resource both to take variable definitions from, and with which to learn how line commands are constructed. To help you identify cell and table references we have provided the entire SAS table layouts for 1971, 1981 and 1991, which give the cell and table numbers of all available counts.
Technical Details About Matching Areal Units From Census to CensusTables for Districts, Counties, Regions and the whole of Britain incorporate all of the 459 1981 and 1991 shipping wards (to which the 216 1971 shipping EDs have been allocated). These tables will thus only differ from those in the census volumes due to the cumulative addition of Barnardised values and the exclusion of restricted ward's values upon aggregation. They should otherwise exactly correspond with output from SASPAC 4. Restricted wards are not explicitly flagged in the dataset. The 1971 and 1991 cell values were generated by aggregating each 1971 ED and 1991 ED to the ward of its nearest 1981 ED. Each 1981 ward is allocated at least one 1971 ED. Around a dozen typing errors in the 1971 (and a couple in the 1981) coordinates were identified and corrected. Thousands of errors in the 1991 coordinates were corrected. It should be realized that other errors in the 1971 data remain; for instance 14 EDs in North Dorset were missing from the 10% 1971 tapes and half a dozen EDs have probably been incorrectly allocated to a ward in Falkirk as their coordinates (from the 100% population tapes) were plausible but differed markedly when cross checked (with the 100% household tapes). Out of 125,476 1971 EDs these number represent quite low rates of known error. Here, tables for the 1971 cell values are supposed to correspond to boundaries in 1981 and will therefore tend not to exactly match figures from the 1971 census volumes. Almost all discrepancies for standard areas should be of differences below one percent however, and reduce as the level of aggregation increases. They will be caused by the transposition to a different area of one or two 1971 EDs lying near the boundaries being used. The effects of Barnardisation and the exclusion of restricted EDs also apply, of course, and increase the apparent discrepancy between published totals and those produced by this program - but hopefully not markedly! |
| Project Home | lct 1.1 Jul 30 2007 |
to extract the data you have asked for from the package's database.
Click 
.
You can 
underneath the 'Search by date' heading. 
and you will be returned to the 
you will see the variety of boundary sets available under that heading.
if
you would like to add the name or label of the areal unit to which each
line of your data refer. 
on
the selection page. N.B. You must have selected
some data to extract before you can access the calculator page. 
(Add
to expression) button and observe that the code has now appeared in the
Expression: box, as shown here: 
as appropriate. In this example, if you selected the code for total population
in 1981 (code 50) and clicked 
to tell the package you want to include the calculation in the extraction.
The package will automatically evaluate your expression and convert it
into a syntax which will ensure the mathematical operators (+ and -) work
in the right way. Do not worry if the expression in the command line area
looks a bit different to how you expected it to look, especially if it
appears to have altered + signs to -'s or vice versa. 
,
then simply click on the variable in the 'Select a cell' box then click
on