Object points

This approach was devised at the Ixonard N. Stern School of Business, New York University. It has similarities with the FP approach, but takes account of features that might be more readily identifiable if you are building a system using a high-level application building tool. The reader should be warned that despite its name.

the technique has no direct bearing on object-oriented techniques. The approach uses counts of the screens, reports and 3GL components that an application might possess - it is these that are referred to as objects. Each object has to be classified as one of the following:

Table 5.6 and Table 5.7 show the scheme used to make this classification. The numbers of objects at each level are multiplied by the appropriate complexity weighting shown in Table 5.8. The weighted sub-totals are then summed to get an overall score for the application.

Table 5.6 Object Points for screens

Number of views contained

Number and source of data tables

Total < 4 Total < X Total > 7 (<2 ser\fers (<3 ser\*ers (>3 servers <3 clients) 3 to 5 clients) > 5 clients)


simple simple medium

3 to 7

simple medium difficult


medium difficult difficult

In other development environments, other types of object and other weightings would be more appropriate.

Further details can be found in R. Kauffman and R. Kumar s report Modelling Estimation Expertise in Object Based ICASE Environments', Stern School of Business. 1993.

Table 5.7 Object Points for reports

Number and source of data tables

Number of sections contained <%? clients) 3 to 5 clients) > 5 clients)

< 2 simple simple medium

2 or 3 simple medium difficult

> 3 medium difficult difficult

Table 5.8 Object Points complexity weightings

Complexity weighting

Object type


Medium Difficult



2 3



5 8

3GL component



Some of these objects might not need to be developed as there are already existing components that can be utilized. The object point score can be adjusted to take this into account. Say that in an application containing 840 object points, 20ri can be supplied by using existing components, then the adjusted new object points (NOP) score would be:

Finally a productivity rate (PROD) has to be identified. It would be best if the estimator could use details of past projects to derive this. As an example, the developers of object points have published the details in Table 5.9 to calculate PROD. In the situation where this information was gathered, as the CASE: tool's features were improving with successive releases, so the experience of the developers with the tool was grow ing too.

Table 5.9 Object point effort conversion

Developer's experience and capabiHty/ICASE maturity and capability


Low Nominal His; h

Very high



7 13 25


An estimate of the person-months needed to carry out the project is then calculated by dividing PROD into NOP. For example, given the 672 new object points above and a development environment where productivity was nominal, then the estimated effort for the project would be 672/13 = 52 months.

Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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