The PASS Data Interaction Point Method (DIP Method)

The Data Interaction Point method of the PASS Consulting Group is a function-oriented size metric (see: Methods for measuring the Size of Software). It counts data elements which are involved in interactions of the considered system with the actors of its use cases, which can be human users as well as other systems. Complexity is considered by different weights of the counts, e.g. when input elements of a dialog have a higher weight than display elements.

Interactions to be counted by the
Data Interaction Point Method

The basic principles, i.e. the orientation on use cases and the counting of data objects from the external view of the actors are the same on which the Function Point Analysis (FPA) and the COSMIC method are based on. However, a major difference to the FPA is the level of detail for counting. FPA counts e.g. data structures, where the score depends of their number of data element types and record element types defined by open-ended interval scales with only three steps. The DIP and the COSMIC method directly count data elements. While COSMIC does not distinguish score values the DIP method derives them by the usage of data elements, e.g. whether they are for read-only or for read-write access, and thus oriented towards the interactional complexity.

The DIP method is better suited for benchmarking size-related KPIs, e.g. the productivity (see: KPIs for Controlling in Software Maintenance and Development).