Establishing a Requirements Baseline by Functional Size Measurement Patterns

[Context] The requirements baseline is an agreed-upon set of desired product features committed to a specific release. It determines intraand interproject planning and involved performance assessment. [Problem] To establish a credible baseline, one which fits into the limits e.g. time box of the project and which satisfies user expectations, a reasonable choice of requirements must be made. This demands commensurable units of measure for requirements that are meaningful to most decision makers in a project team. [Principle Idea] This work proposes the use of functional size measurement patterns as a reusable point of reference to classify requirements consistently and to estimate their functional size in a reproducible way. It develops measurable requirements patterns out of problem frames and a counting procedure, that facilitates determining function points for requirements in accordance with ISO/IEC 20926:2009. [Contribution] These patterns provide the project team with a bias-free anchor regarding the functional size of requirements with which they can correlate their requirements estimates and anticipated work plan. Establishing the requirements baseline with respect to these patterns eases the comparability of project outcomes and thus contributes to the predictability of project planning.