Variables define pieces of information required by the logic engine to context filter, branch, etc, within a process data module. Variables can be global or local in scope. Local variables are defined in the element <variable> described below. Local variables are only available to the process data module in which they are declared.If a variable must be available to several process data modules, it must be declared in the ACT or CCT as a product attribute or condition. It will then be recognized by the logic engine as a global property and made available to all process data modules. Refer to Chap 3.9.5.3.1 and Chap 3.9.5.3.2 for descriptions of the element <productAttribute> and the element <condition>. More information is provided in Chap 4.14.1 and Chap 4.14.2 on these concepts.In the process data module, the element <productAttribute> and the element <condition> can be used in the applicability structure as well as in expressions, assertions, etc. These elements are initialized in the PCT. They will not have a dialog as part of their content compared to local variables. However, they have a prompt available in their definitions which can be used to query the user for the value of the product attribute or condition as well as enumeration label attributes which can be used as menu choices in an IETP software constructed dialog. Dialogs, such as are defined for local variables, can also be authored for global properties on the element <dmNode> or the element <proceduralStep>.