Functional and Non-functional Size Measurement with IFPUG FPA and SNAP — Case Study

Conference paper
Part of the Advances in Intelligent Systems and Computing book series (AISC, volume 349)


Software size measures are probably the most frequently used metrics in software development projects. One of the most popular size measurement methods is the IFPUG Function Point Analysis (FPA), which was introduced by Allan Albrecht in the late-1970’s. Although the method proved useful in the context of cost estimation, it focuses only on measuring functional aspects of software systems. To address this deficiency, a complementary method was recently proposed by IFPUG, which is called Software Non-functional Assessment Process (SNAP). Unfortunately, the method is still new and we lack in-depth understanding of when and how it should be applied.

The goal of the case study being described in the paper was to investigate how FPA and SNAP measurement methods relate to each other, and provide some early insights into the application of SNAP to measure the non-functional size of applications.

The results of the study show that SNAP could help mitigating some well-known deficiencies of the FPA method. However, we have also identified some potential problems related to applying SNAP in a price-per-size-unit pricing model.


IFPUG Function Points FPA SNAP size measurement 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Aguiar, M.: When metrics mean business. In: Proceedings of the 9th Software Measurement European Forum, pp. 1–12 (2012)Google Scholar
  2. 2.
    Albrecht, A.J.: Measuring application development productivity. In: Proceedings of the Joint SHARE/GUIDE/IBM Application Development Symposium, pp. 83–92 (October 1979)Google Scholar
  3. 3.
    Conover, W.J.: Practical Nonparametric Statistics, 3rd edn. John Wiley & Sons (1999)Google Scholar
  4. 4.
    IFPUG. Function Point Counting Practices Manual, Release 4.3.1 (2010) ISBN 978-0-9753783-4-2Google Scholar
  5. 5.
    IFPUG. Software Non-functional Assessment Process (SNAP) — Assessment Practices Manual, Release 2.2 (2014) ISBN 978-0-9830330-9-7Google Scholar
  6. 6.
    ISO/IEC. 25010: 2011: Systems and software engineering–Systems and software Quality Requirements and Evaluation (SQuaRE)–System and software quality models (2011)Google Scholar
  7. 7.
    Kopczynska, S., Nawrocki, J.: Using non-functional requirements templates for elicitation: A case study. In: 2014 IEEE 4th International Workshop on Requirements Patterns (RePa), pp. 47–54. IEEE (2014)Google Scholar
  8. 8.
    Kopczynska, S., Nawrocki, J., Ochodek, M.: Software development studio—Bringing industrial environment to a classroom. In: 2012 First International Workshop on Software Engineering Education based on Real-World Experiences (EduRex), pp. 13–16. IEEE (2012)Google Scholar
  9. 9.
    Nawrocki, J., Olek, Ł., Jasinski, M., Paliświat, B., Walter, B., Pietrzak, B., Godek, P.: Balancing agility and discipline with XPrince. In: Guelfi, N., Savidis, A. (eds.) RISE 2005. LNCS, vol. 3943, pp. 266–277. Springer, Heidelberg (2006)CrossRefGoogle Scholar
  10. 10.
    Tichenor, C.: A new metric to complement function points. CrossTalk—The Journal of Defense Software Engineering 26(4), 21–26 (2013)Google Scholar
  11. 11.
    Yin, R.K.: Case Study Research: Design and Methods. SAGE Publications (2003)Google Scholar

Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  1. 1.Faculty of Computing, Institute of Computing SciencePoznan University of TechnologyPoznańPoland

Personalised recommendations