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IMPS - Getting Started

IMPS 4.1

U.S. Bureau of the Census


What is IMPS?

The Integrated Microcomputer Processing System (IMPS) is a software package for entry, editing, tabulation, management, and dissemination of census and survey data. This release continues progress toward a complete Windows version of IMPS. It is a combination of IMPS 3.1 for DOS and several Windows modules. IMPS 4.1 lets you create and maintain data dictionaries, perform cross-tabulations with or without geographic areas, sort data files, view table and text files, and display geographic area tabulations as thematic maps.

During installation, both the Windows and DOS parts of IMPS are installed on your computer.

New Features in IMPS 4.1

  • Map Viewer - Displays thematic maps of one variable or the ratio or difference of two variables. Can receive exported tabulated data from CrossTab.
  • Data Sort - Sorts a data file (up to 2 Gbytes in size) either by questionnaires or by records.
  • Data Dictionary - Automatically converts dictionaries between IMPS 3.1 and IMPS 4.1. Allows definition of more complex record hierarchies (for example: household, family, person). CrossTab can tabulate data items between any of these records.
  • Cross Tabulation - Produces tables by geographical areas, like IMPS 3.1 CENTS, as well as for the entire file. Uses an Area Names file to add the geographic area names to the tables. Tabulated values can be exported to Map Viewer.
  • Table Viewer &amp Text Viewer - More control is available for printing. Both viewers allow definitions of margins, headings and footings. The text viewer allows different font sizes for printing.


Hardware and Software Requirements

A minimum configuration:

  • 33MHz 486 processor
  • 16MB of RAM
  • VGA monitor
  • mouse
  • 17MB of free hard drive space (6MB if you already have IMPS 3.1 installed)
  • Microsoft Windows 95

A recommended configuration:

  • Pentium processor
  • 16MB of RAM
  • SVGA monitor (PCI or VESA graphics)
  • mouse
  • 17MB of free hard drive space (6MB if you already have IMPS 3.1 installed)
  • Microsoft Windows 95, Windows 98, Windows NT

Installation Procedure from Diskettes

  • Place Disk 1 of IMPS 4.1 in your diskette drive.
  • Click the Start button on the taskbar.
  • Click Run option.
  • Enter a:\setup.
  • Click OK.

Installation Procedure from the WWW

  • In option "Downloading" select IMPS 4.1
  • Select a folder to save the file "imps.exe"
  • Go to folder and double click on "imps.exe" to install software

The setup takes you through a series of dialog boxes that prompt you for setup information. Accept default values if you have any doubts.


To start IMPS:

  • Click the Start button
  • Highlight the Programs line
  • Then highlight IMPS 4.1 line next to Programs
  • Then highlight and click IMPS 4.1 line next to IMPS 4.1.

The following toolbar will appear on your screen.

IMPS Taskbar

Press any of the buttons on this bar to start an IMPS 4.1 module. The modules from left to right are:

  • Data Dictionary
  • Cross Tabulation
  • Text Viewer
  • Table Viewer
  • Map Viewer
  • Data Sort
  • IMPS 3.1 (DOS Version)
  • Microsoft Explorer (to manipulate files on your disk)

You will want to start your use of IMPS 4.1 by creating or viewing a Data Dictionary.

Data Dictionary

Press the Data Dictionary button data dictionary button on the tool bar. A dialog box will open, asking you for a Data Dictionary file name.

data dictionary screen shot

You can do the following:

Select the Data Dictionary Popstan.ddw in the IMPS41\Projects\Examples folder and press the Open button to inspect and edit it.


Press the Cancel button to create a new Data Dictionary.


Move to another folder to find an existing IMPS 3.1 or IMPS 4.0 Data Dictionary. IMPS 3.1 Data Dictionaries have the extension .dd, while IMPS 4.0 Data Dictionaries have the extension .ddw.

Try selecting Popstan.ddw and pressing the Open button.

data dictionary screenshot

IMPS is questionnaire-oriented, that is, it processes data files by questionnaire. The Data Dictionary module is used to create and maintain a description of the organization of a questionnaire in the data file. The other modules of IMPS use this Data Dictionary description to access data files.

A questionnaire can contain a single record, multiple records of the same kind, or multiple records of different kinds. If any questionnaire contains multiple records, then the questionnaire must have one or more Questionnaire ID items. These items, usually geographic codes and household or establishment codes, uniquely define all the records that belong to any given questionnaire.

In the Popstan Data Dictionary (Popstan.ddw) shown above, there are two kinds of records (record types), Person and Household. Because more than one kind of record exists, questionnaire ids are defined: Province, District, Enumeration Area, Building Number, and Housing Unit Number.

The Questionnaire Window shown above contains general information:

  • a label for the Data Dictionary for use in report listings.
  • the data items used as questionnaire ids.
  • the size and location of the record type code.

Each different kind of data record has attributes:

Record Label Identifier used by the Windows modules to refer to the record
Name Identifier used by the DOS (IMPS 3.1) modules to refer to the record
Type Value The value the record type for this kind of record
Required Whether this record must be present or not in each questionnaire
Hierarchy Hierarchy level of this record
Max Maximum number of records of this type which may be present in a questionnaire

Each of these attributes can be changed by clicking on them. Use the Add, Insert, or Delete buttons to add or remove records.

Questionnaire ID items are selected from the Common items. These items occur in the same position on each record. They are defined in the Common items Window of the dictionary. Items for each type of record are defined in the Record items Window of the dictionary. Use the following buttons to move between these windows.

questionnaire button Questionnaire Window (yellow marks)
common items button Common items Window (dark blue marks)
record items button Record items Window (light blue marks)

The Common items and Record items Windows are split. The top half contains a list of items:

Item Label Identifier used by the Windows modules
Name Identifier used by DOS (IMPS 3.1) modules
Data Type of data in the item (Numeric, Alphanumeric, or Mixed)
Item Complete item or subset of a larger item (Item, Subitem)
Start Location in a data record where the item begins
Len Number of digits/characters in the item
Occ Number of adjacent occurrences (repeats) of the item
Dec Number of decimal places in the item (numeric only)
Sign Whether the item is signed (can have negative and positive values)

The bottom half contains a list of sets of values or categories of the item highlighted in the top half of the screen:

Value Set One or more names for a specific set of values which can be used to classify the data values associated with the data item
Value Label Label for a value or range of values
From A single value or the beginning value in a range
To Blank for a single value or the last value in a range

If you press the Common items button, common items button, you will see the following screen:

common items screenshot

All the items listed here occur on both the Person and the Household records, that is, they are common to all the different record types. The values for the item highlighted at the top of the Window appear at the bottom on the Window. Each of the attributes can be changed by clicking on them.

You can use the Add, Insert, and Delete buttons under the toolbar to add and remove items, value sets or individual values. The buttons refer to items if an item is highlighted. They refer to values if a value set or value is highlighted.

If you press the Record items button, record items button, you will see the following screen:

record items screenshot

The data item Age is selected. Two value sets associated with Age are shown. The first is required to have the same name as the item label. The second, Age in 5 Year Groups, is a user-defined name. By defining different value sets, you can develop different categorizations for tabulation.

To move between different type records, select the record name from the drop list box under the toolbar. You can also use the arrow buttons to the right of the box.

The following buttons are useful to move records, items, and values around, reverse changes you have made, and for manipulating text in record, item, or value labels.

cut Cut
undo Undo (reverse changes)
copy Copy
paste Paste
find Find

You can use the Layout button layout to produce a graphic view of the records. An example is shown below.

layout screenshot

To produce a listing of the Data Dictionary, use the Report button . Clicking this will allow you to select either a summary listing (names of records and data items only) or a detailed report (summary plus all the value sets associated with the data items).

report screenshot

Text Viewer

You can use the Text Viewer to look at the contents of any text file. The file can be up to 32,000 characters wide and indefinitely long. IMPS uses the Text Viewer to display the Data Dictionary listing (see previous page) and tabulation error reports. You also can use the Text Viewer to look at data files.

textview You can start the Text Viewer from the IMPS 4.1 Taskbar button or from the Tools menu option of the Data Dictionary or Cross Tabulation. You can also use it to examine a text file from the Windows Explorer. Right click on the name of a text file. Select Send to and then TextView. The Text Viewer can view multiple files at the same time. By using the Window menu option, you can place files side by side vertically or horizontally.
find You can use the Find button to search for text within a file. The search begins at the top of the current screen. You can search both forward and backward. The search strings used previously are remembered.
print You can print all of the file (or part of the file, if you have selected (highlighted) text), by pressing the Print button.
font You can change the size of the print font by pressing the Font button.
print setup You can change the margins and place headings and footings on the printed file by pressing the Print Setup button.
print preview You can see what your printing will look like before you send it to the printer by pressing the Print Preview button.
copy You can use the Copy button to copy selected text from the viewer to other applications, such as text editors or word processors.
copy for spreadsheet You can press the Copy for Spreadsheet button to copy table text to a spreadsheet. Select the rows and columns you want to copy, before pressing the Copy for Spreadsheet button. Values separated by two or more blanks will appear in different columns in the spreadsheet. Try copying text from the Data Dictionary report to a spreadsheet.

In the example below, the Popstan.dat file is being viewed.

text viewer screenshot

You can press the Ruler button ruler to show the line and character position of the text. You can select text or data within the file to copy and paste into another application, save to another file or print. For example, you may want to copy several questionnaires from a large data file to create a smaller file for testing.

You can use the Goto button to locate a particular line in the file. For example, when errors occur in tabulation, you are given the record number where the error occurred. Use the Goto button to locate the record in error.

Cross Tabulation

To perform cross tabulations, press the Cross Tabulation button cross tabulation on the Data Dictionary toolbar or on the IMPS 4.1 taskbar. The screen (similar to that shown below) will appear. You can perform cross-tabulations on up to four data variables: two Row Items and two Column Items. You can show the tabulated results as totals, percents or both. You can tabulate a Value, such as income, and use a Weight in the tabulation. Specific records can be selected as a Universe for inclusion in the tabulation. In addition, tables can be produced for geographic Areas.

Press the Item buttons to select or change items. You can type the name of the item or click on an item to select it. Press OK to complete the selection or Remove to delete the selection. The list of items normally appears in alphabetic order. Your can change this to the order that the item appear on the records.

The table title is generated and modified automatically. If you don't like the generated title, you can change it by changing the text in the title box, and then checking the lock box to the right.

cross tabulation screenshot

Use the Add, Insert, and Delete buttons under the toolbar to add, insert, and delete tables.

Pressing the Universe button allows you to create a filter to select only certain records for tabulation. You can select one or more conditional expressions of item, relation, and value. An example of such an expression is:

sex = female and age >= 12

Pressing the Area button allows you to create multiple table panels by geographic area. To produce tables by area you must select at least one Area Id and you must have an area names file. You can create an area names file using the CENTS module of IMPS 3.1. You can also create one with a text editor using the Popstan.anm file as a model. Every tabulation in a run has the same area selection. If no row items are selected, the area names will be the table rows.

You can create a frequency distribution for any item by selecting it as the row item and not selecting any column items. This will create a table with two columns, frequency and cumulative frequency.

There is a check box to Include undefined row and column. Checking this box will create a extra row or column for each item you tabulate. The extra rows and columns give counts of the number of out-of-range values for each item. Choosing from the menu Options/Dump Undefined will cause each undefined value to be dumped in a log file, together with questionnaire and record identification.

If you want to change or view your Data Dictionary, you can press the button.

Try to create a table. Select Relationship = Head as the Universe. Select Province and District as the Area Ids. Choose Popstan.anm as the area names file. Select Sex as the column item. Do not select a row item. The geographic areas will be the row of the table.

Press the Run tabulation button run tabulation to perform the tabulation. Use the Popstan.dat file as the input file.

Table Viewer

When a tabulation is completed the Table Viewer displays the results as shown below:

table viewer screenshot

If the tabulation is not exactly what you wanted, use the back button back to return to respecify your cross-tabulation. If the tabulation is what you wanted, you can print it, save it to a file, or copy it to a word processor or spreadsheet.

The Page Setup page setup and Print Preview buttons print preview are available to change the margins, heading, and footing for printing and to preview the print image. You can also change the font size and style for the table by pressing the Font font button.

In Table Viewer you can select rows and columns to print, save, or copy. The rows or columns do not have to be adjacent. To make a selection, move the cursor to any table cell and press the left mouse button down. While holding down the left mouse button move the cursor over the other cells to be included, then release the button.. The selected cells turn green. When the left mouse button is released, the stubs and column headings associated with these cells are also highlighted. To select additional cells, hold the Ctrl key down while you make your additional selection. To select the entire table, click the Edit and then Select All from the menu.

If the table you are viewing was produced using Area and an IMPS Map Viewer map is available with the same area codes as used in the tabulation, you can produce a thematic map of the tabulated data directly from the Table Viewer.

To create a thematic map, select a data cell from the table you are viewing, for example, a cell from the Total column, by clicking on it with LEFT mouse button. Then click the RIGHT mouse button and select Map or press the Map Viewer button map viewer on the toolbar.

You will be asked for an IMPS map file. For this example, choose Popstan.mpc. Map Viewer will display a map showing the tabulated values of all the provinces in Popstan.

To add another variable to the map, switch back to the Table Viewer by selecting its button on the Windows taskbar (usually at the bottom of the screen). DO NOT exit the Map Viewer. Select a cell from another column, for example a cell from the Female column, and press the Map Viewer button. Notice that the variables available for mapping are Total and Female.

Map Viewer

Pressing the Map Viewer button map viewer on the Table Viewer toolbar or the IMPS 4.1 taskbar provides an easy way to present tabulated data in a thematic map. In the previous section you invoked the Map Viewer twice to display two sets of tabulated values: the Total number of Household Heads, and the total number of Female Household Heads.

The second variable, (Female) should be currently displayed. Pass the mouse cursor over the map. Notice that the cursor changes to a magnifying glass. This means you can "drill down", or descend to a lower map level, by clicking the left mouse button. You will see the districts within the province you click on. Press Esc key to go back to the Popstan map. The map of Popstan shows the provinces in different colors. You can show all the districts in the country by clicking the drop-down list (above the country and province list) and selecting District. By clicking the right button while on the map, you can see the exact number of female household heads for a given district.

The hierarchical tree on the left side of the screen gives another way to move around among geographic units. The + in front of the names shows there is more geography available. Click on the + in front of a province name to show the districts in that province. Click on any province name itself to display the thematic map of that province. Click on any district name to outline in yellow the district in the province map. To close up the geographical listing, click on the - in front of the name.

To change the number of intervals, the ranges of each interval, the colors which the map uses and the text in the legend box, click on the legend box with the right mouse button. To change the title text and/or font, click on the title with the right mouse button. The title can be more than one line; use Ctrl+Enter inside the box containing the title to make new lines. With a little practice, you will be able to produce high quality thematic maps with minimal effort.

You can change the variable which is displayed on the map. Click on the drop-down list labeled Variable. You can also compare two variables. Click on the drop-down list labeled Base Variable and select Total. This will display the Percent change defined as

[(Variable - Base Variable) / Base Variable] * 100%.

Click on the Calc drop-down list to change the way the two variables are compared. The Percent statistic would seem more reasonable in this example: percent of households with female heads. If you select Percent, the map shown below should appear.

Use the Print button to print your map, or the Copy button to copy it to a word processing document.

map viewer screenshot

To save the data variables you have brought into the Map Viewer, press the Save button and create a new map data file (.mdf). You can open this map data file directly from IMPS 4.1 by starting the Map Viewer and then selecting the .mdf file which you just created. (Note: When a map data file is opened only the first variable is mapped.)

The map data file (.mdf) contains the variables and their values for each geographic unit. You can make your own or change one you saved by using standard spreadsheet software. Data from previous censuses or surveys can be entered into the file. See Help for a description of the Map Data File and how to modify it.

The map data file is associated with a map file, which contains the map polygons, area codes and names for each geographic area. Usually two or three levels of geography are adequate for thematic maps. You need to create this file first, before generating or making your own map data files. The format of the map file is given in the Map Viewer Help. If you already have a digitized map file, either in ArcView or Atlas GIS format, we can assist you in converting it to our Map Viewer format. (Contact us for more information.)

Data Sort

Pressing the Data Sort button data sort on the IMPS 4.1 taskbar allows you to sort files up to two gigabytes. Since the questionnaire is the unit of processing for IMPS, sorting is performed on questionnaires, not records. (To sort the data file on records, you must create a Data Dictionary for the file which defines only one kind of record which occurs only once.)

Once you have selected a Data Dictionary, you are presented with a list of Questionnaire Ids to use as sort keys. Select Questionnaire Ids from the left-hand column. Click the > button to make these item keys. You can use the >> button make all the items keys. You can remove keys by selecting them and pressing the < button. The << button removes all the keys.

You can use the Move Up and Move Down buttons to move a particular key up or down the list of keys to obtain the required order (major to minor). Select the key to move, then press the button.

You can use the Ascending (small to large) and Descending (large to small) buttons to change the sort order for a key. Again select the key, then press the button.

Once you have select the keys, press the Run Sort button run sort. You will be asked to enter:

  • the name of the input data file
  • the name of the sorted output data file
  • the name of a folder where the temporary sort work file is written

It is important to remember that no matter what the data file size, there must be at least twice the data file size of free space (intermediate work file(s) + final sorted file) in order to complete the sort. This free space does not need to be on the same device as the file being sorted.

The sort specifications (keys and ascending/descending switches) can be saved in a sort specification file which will have the extension .ssf.

data file sort screenshot

Some important notes regarding the Data Sort:

  • If the data file has duplicate Ids (two questionnaires with the same Id values), the Data Sort will abort with an error message giving the duplicate Id values..
  • The record type item is NOT available for sorting questionnaires.
  • If the questionnaire has only one record type and only one record per questionnaire (maximum records = 1), all the data items on the record are available for sorting.
  • Data Sort will make sure, before the sort, that enough disk space is available for the sort to complete successfully.


To use the modules from IMPS 3.1, press the DOS IMPS button on the IMPS 4.1 taskbar. The following dialog box will appear. Select the folder you want to be your default directory while using IMPS 3.1 modules. The example files for IMPS 3.1 are in the ..\imps31\bench folder.

dos IMPS Screenshot

Once you have selected a default folder, you will enter the DOS IMPS 3.1 system. There is printed documentation for each of the IMPS 3.1 modules. This documentation is available in WordPerfect 5.1 format.

The CONCOR and CENTS modules of IMPS, use a COBOL compiler, which is contained on your installation diskettes. (Note: The Internet version does not contain this compiler.)

Most of the functions of the QUICKTAB module of DOS IMPS are provided in a much better way in the Windows Cross Tabulation module. However, for creating frequency distributions of all the items in data file, you will want to use the Frequency part of QUICKTAB.

dos menu

The DOS version of IMPS uses a different Data Dictionary that the Windows version. In the DOS version the Data Dictionary file extension is .dd, while in the Windows version the extension is .ddw. You can save most, but not all, Windows Data Dictionaries in the DOS format. To save a Windows Data Dictionary in DOS format, use the File/Save As menu option and set the file extension to .dd. The DOS Data Dictionary is required by the CENTRY, CONCOR. CENTS, QUICKTAB and CENVAR modules of DOS IMPS.

Using Online Help

To obtain information on how to use IMPS 4.1 modules, press the Help button help. The Index tab, shown below provides an easy way to search for information on a particular topic. Use box 1 to type in a word, or use box 2 to click on the index entry.

help screenshot

You can use the Contents tab to look through the helps by topics, like a book. The Find tab allows you to locate the use of any particular word in the help documentation.

You can print any page of the help by pressing the Print button at the top of the help screen. You can also print groups of help pages from the Contents tab.

Input and Output in Other Languages

While IMPS menus and documentation are only in English, most of the information you supply can be entered and displayed in your own language. For example, Data Dictionary labels and notes can be entered in languages other than English. Data entry screens and tables can appear in other languages.

During installation, you are asked what language you want to use for your tables and maps. If you choose a language other than English, then small words like Table, Total, to, Legend, Percent, Ratio, and so on, which appear in CrossTab tables or Map Viewer maps will appear in the language chosen.

User Support

International Programs provides user support for IMPS without charge to national statistical offices and certain international organizations. It also provides, on a contract basis, training in the use of IMPS for census and survey processing. From time to time, it conducts IMPS workshops in Washington.

Source: U.S. Census Bureau | International Programs |  Last Revised: 2012-12-20T10:08:32.909-05:00