Define bands (Extracts)

The Define bands page enables you to redefine bands in a numeric variable.

Bands are ranges of numeric data, such as ages from 5-9 years, 10-14 years, 15-19 years, and so on. You might wish to redefine the bands into longer or shorter intervals than the current five years. (Bands do not have to all have the same interval. To create bands with different intervals, see the Modify section of this page.)

Redefining bands works by creating a new variable. To start redefining bands, first enter a name for the new variable that will be created. The New variable name field initially shows the original name with a number appended to it. You can accept the default or enter a new name.

Note: The new variable will appear in alphabetical order in the same category as the original. In most cases it is best to accept the default name, because it is guaranteed to be unique.

Initialize

Use this area to enter the lowest value in the new variable and a constant numeric width for all the bands. You can either use these settings or modify them in the Modify area, below.

Start

Enter a value that is lower than or equal to the lowest value in the variable, as shown in the Code area.

Increment

Enter a width for the bands.

Create bands

Click to create the new bands. Codes are assigned to the bands and they are displayed in the Code area.

Modify

Use this area if you want to create bands of unequal size.

First select a band to modify in the Code area, and then enter the required information.

New code

Assign a new code to a band.

Renumber

Sequentially renumbers all the codes starting from the entry in New code.

Minimum

Enter a value for the lower limit of the band. If you want the band to include the limiting value, click Inclusive.

Maximum

Enter a value for the upper limit of the band. If you want the band to include the limiting value, click Inclusive.

Note: When displaying a band, an inclusive endpoint is shown by a square bracket and an exclusive endpoint is shown by a round bracket. It is possible for one endpoint to be inclusive while the other endpoint of the same band is exclusive. Therefore bands can start and end with different kinds of brackets.

Insert

Adds the new bands and their definitions to the Code area.

Delete

Removes bands from the Code area.

Apply

Creates a variable with the new bands. The new variable appears in the Extract tab in alphabetical order. Clicking the name of a rebanded variable opens its Show reband page.

Example

This example shows how to group two different non-adjacent bands together.

In an "Age" dimension, we will group the outlier age ranges: 0-15 years old, and 65 years and older, into one band. The rest of the ages we will group in 5 year increments.

1. Set Start: 0 and Increment: 5, and then click Create bands. This will create the initial bands.
2. Click on Code 1 [0,5) and change the Maximum to 15. Make sure Renumber is checked beside it so that the codes will still be sequential.
3. Click Insert.
4. Scroll down to Code 12 [65,70) and change the Maximum to 100 (or whatever the largest value is).
5. Change the New code to 1 and uncheck the Renumber check box next to New code.
6. Click Insert.

If you look at the codes you will see a code number 1 at the beginning of the list and another code number 1 at the end of the list. When the report is created these will be merged together into the same code 1.