Cognos reports that use Windchill Data Sources require every parameter value to be specified. However, a report can be more useful, if the user can optionally leave parameter values unspecified and the report ignores the related criteria or implicitly uses a suitable default. To achieve this behavior, it is possible to pass a parameter value consisting of a single space (“ “) and by making a single space the default value for the parameter in you input page, the user will not be required to enter anything into the parameter input field. When using this technique, you must ensure that the underlying Data Source will be able to properly handle the empty space values that are passed.