Metrics for Specification Quality nr nf nnf nr

Metrics for Specification Quality nr = nf + nnf nr – total number of requirements nf – functional requirements nnf – non-functional requirements Lack of ambiguity: Q 1 = nui/nr nui – number of requirements for which all reviewers had identical interpretation (i. e. unambiguous requirements)

Summary of Today’s Lecture

Software Engineering II Lecture 14 Fakhar Lodhi

Recap

Metrics for Specification Quality Completeness Q 2 = nu/[ni x ns] nu – unique functional requirements ni – number of inputs (stimuli) ns – number of states specified

Metrics for Design Model Architectural Design Metrics – Structural complexity S = (fout)2 – Data complexity D = v/(fout + 1) • ‘v’ is the number of input and output variables – System complexity C = ∑ (Si + Di)

Baseline ‘Data colleted from past projects’ • Data must be reasonably accurate • Data should be collected over many projects • Measures must be consistent – same technique or yardstick for data collection • Applications should be similar to work that is to be estimated • Feedback to improve baseline’s quality

Metrics for small organizations Small organizations – around 20 or so people • Must measure in a cost effective manner – Simple and value oriented – Focus on result rather than measurement – What to measure – objective of measurement

Example Objective: Reduce the time to evaluate and implement change requests You need to measure • Time (in hours or days) elapsed from the time a request is made until evaluation is complete - tqueue • Size (fp) of the change request • Effort (in person months) to perform the evaluation. Weval • Time elapsed from completion of evaluation to assignment of change order – teval • Effort required to make the change – Wchange • Time required to make the change – tchange • Errors uncovered during work to make change – Echange • Defects uncovered after change is released – Dchange