Modeling Guide

Date Variance Type

Use Date Variance to output randomized dates.

Set the options to alter input dates based on a date variance type (set number of days, months, years, or within a set range).

When using the fixed days, months, and years options, the application generates an internal calculation based on the variance number. For example, if you have an input value of "May 27, 2005" and select Fixed Months and a variance of three, then the calculated minimum and maximum dates are Feb 27, 2005 and Aug 27, 2005. If you have set a user-defined minimum date of Apr 1, 2005 (within the calculated minimum value), and a user-defined maximum date of Dec 31, 2005 (outside the calculated maximum value), then the new valid range is April 1, 2005 (the user-defined minimum) through Aug 27, 2005 (the internally calculated maximum value).

Option Description
Variance Type

Define how you want to vary a date.

Fixed days: Varies the date by a fixed number of days that occur before or after the input date.

Fixed months: Varies the date by a fixed number of months that occur before or after the input month.

Fixed years: Varies the date by a fixed number of years that occur before or after the input year.

Range: Varies the date within the user-defined minimum and maximum dates that you set. You must set the Minimum and Maximum date values.

Variance Required for the variance types (days, months, years). Determines the number of days, months, or years by which to randomize the input. Enter a value greater than zero.
Minimum date Required for range variance, and optional for fixed date variance types. Enter a date, or select a value by clicking on the calendar icon. The minimum acceptable date value is Sep 14, 1752.
Maximum date Required for range variance, and optional for fixed date variance types. Enter a date, or select a value by clicking on the calendar icon. The maximum acceptable date value is Dec 31, 9999.

Example

The following table shows several examples for one date value in a database: May 27, 1995. The examples help to illustrate how the date is calculated internally, and how it is output when the user-defined minimum and maximum values are used together.

Variance Type Internally calculated date Output value is within this range Notes

Fixed Days

Variance: 10

Minimum date: <not set>

Maximum date: <not set>

Min date: May 17, 1995

Max date: Jun 6, 1995

Min date: May 17, 1995

Max date: Jun 6, 1995

The output uses the internally calculated dates, because the user-defined dates are not specified.

Fixed Days

Variance: 100

Minimum date: Mar 1, 1995

Maximum date: Aug 31, 1995

Min date: Feb 9, 1995

Max date: Sep 4, 1995

Min date: Mar 1, 1995

Max date: Aug 31, 1995

The user-defined minimum and maximum dates are within the calculated minimum and maximum dates. Therefore, the user-defined dates are used.

Fixed Months

Variance: 6

Min date: Jan 1, 1995

Max date: Dec 31, 1995

Min date: Nov 27, 1994

Max date: Nov 27, 1995

Min date: Jan 1, 1995

Max date: Nov 27, 1995

The user-defined minimum date is within the calculated variance, and is the value used for output.

The maximum user-defined date is outside of the calculated variance. Therefore, the maximum calculated date is used.

Fixed Years

Variance: 15

Min date: Jan 1, 1965

Max date: Dec 31, 2015

Min date: May 27, 1980

Max date: May 27, 2010

Min date: May 27, 1980

Max date: May 27, 2010

Both of the user-defined minimum and maximum dates are outside of the calculated variance. Therefore the calculated date is used.

Range

Min date: Jan 1, 1965

Max date: Dec 31, 2015

n/a

Min date: Jan 1, 1965

Max date: Dec 31, 2015

Because there is no variance for range, only the user-defined minimum and maximum values are used.