Why determine the size of my software product?

The size of an information system, product or project is the basis for all application areas such as estimating system development, measuring productivity, benchmarking and project control. Within the field of system development and management, there are several ways to measure the size. Some methods are ISO-standardized, which offers a significant advantage with respect to the global use and management of the method.

When choosing a sizing method the following criteria plays a role:

  • Person independence: the sizing method is independent of the person that determines the size, assuming that the person is trained in the method;
  • Repeatability: the sizing method can be repeated, resulting in a same result as in the previous sizing;
  • Comparability: two independent sizes can be compared with each other, based on objective criteria;
  • Independence of technology: the sizing method results are independent of the technology where the sizing method is applied
  • Applicability in an early stage: the sizing method can be applied in an early stage of the lifecycle, independent whether this is a traditional lifecycle (e.g. Waterfall) or an Agile lifecycle;
  • Simplicity: the sizing method can be easily applied without any additional study or certification
  • Future-proof: the sizing method can be applied now and in the future (next 5 years) without substantial changes in the results;
  • Expression of user value: the sizing method results in an indication of the user value;
  • Expression complexity: the complexity level of the expressions used in the sizing method;
  • ISO standard: the sizing method is an ISO standard and results in an objective size

The following table shows a clear comparison of sizing methods, based on the above aspects:

 FPACOSMICMcCabeStory PointsLOCUse Case Points
= meets
0 = meets reasonable
= does not meet
Person independency
Repeatable0
Comparability0
Independence of technology
Early stage
Simplicity0000
Future proof000
User Value
Expression complexity
ISO standaard

More information

Would you like to obtain more information about sizing? More information can be found in one of the three Nesma whitepapers on sizing: Fuction Point Analysis, Counting topics and Other Sizing Methodologies. Click on one of these titles and get your free download.