CorrespondenceMethod

(new to 4.0) Avail as of 4.0.0.34.

Attribute CorrespondenceMethod

Used as an attribute on an object that serves as an index for an edit Table, DetermTable or ProbTable. Controls how correspondence between previous and new index values is determined when the index value changes.

Possible Values:

1 : Positional

2 : Associative

3 : Flexible Associative (current default)

Description

When an index definition changes, where some elements might be removed, others added, some existing elements renamed, and some existing elements potentially re-ordered, edit tables that use that index need to be re-adjusted. In some cases, the correspondence between the old index elements and new index elements may be ambiguous. This is particularly the case when when the index value is computed.

The CorrespondenceMethod attribute determines the method Analytica uses to determine this correspondence. Consider the following example. Here we have a one-D edit table indexed by Year.

Year	Contribution
2007	$2500
2008	$3000
2009	$3200
2010	$3400

Suppose the index Year is defined as 2007..2010.

Now, Year is changed to 2006..2011. The two most basic correspondence methods are pure positional and pure associative, and would result in the following respective adjustments to the Contribution edit table.

Pure Positional Correspondence 2006 $2500 2007 $3000 2008 $3200 2009 $3400 2010   2011

Pure Associative Correspondence 2006   2007 $2500 2008 $3000 2009 $3200 2010 $3400 2011

There are cases where either form of correspondence may be more desirable. In general, pure associational correspondence may lose more data than positional, since if the original element is removed, the data for that row may be lost.

Flex associational, the default used, corresponds by association when it can (i.e., when the same element appears in both old and new), but draws on positional correspondence between paired elements, which helps to preserve data when an element is basically renamed. Thus, flex associational preserves more data than pure associational.

To change the CorrespondenceMethod attribute for an index, use typescript, e.g.:

 CorrespondenceMethod In1 : 1

Note: In build 4.0.0.34, if the number of elements does not change, pure associational reverts to positional. However, this will be changed. Flex Associational will revert to positional if the number of elements is not changed, but Pure Positional (1) will not.

Notes

Remember that CorrespondenceMethod is a property of the Index, not of the table.

See Also

• Table Splicing