Monday, April 13, 2009

FP (Function Point) Counting should not be done by Application Project Managers / Developers.

Looking at software estimation technique with FP, this technique is suited when we want to estimate the S/W size from a business user perspective. This technique is mainly based on data/functions that cross application boundary and are User Identifiable. Since this is heavily based on what Business User sees as a functinality from the application, i think FP counting should be always done from the Business Users/SME point of view rather than Project Managers of the application. Project Managers always tend to bring technology constraints while doing estimations, and FP should should be tech. independent. I think, the rational behind FP counting can only be achieved if we start estimating it from business user's perspective.
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6 comments:

  1. RajeshApril 13, 2009 at 3:10 AM

    In what stage of the software development cycle should the FP analysis carried out?

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  2. YogeshApril 13, 2009 at 3:18 AM

    Typically, Size is calculated at the start of any projects and revisited/reviewed when major milestones are met and/or enhancement or Changes to requriement happen.

    It is possible to estimate size, effort and cost using Function Point Analysis if:

    o The project is a development / re-engineering project
    o The project is on client-server, open system, Internet or mainframe platform.
    o The application is not heavy on algorithmic components.
    o Customer requirements are clear in terms of data elements being maintained/referenced, External Inputs to the application and External Outputs/Inquiries from the application.

    It is not possible to estimate size, effort and cost using Function Point Analysis if:
    o The application is heavy on algorithmic components.
    o It is not possible to get clear customer requirements in terms of data elements being maintained/referenced, External Inputs to the application and External Outputs/Inquiries from the application.

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  3. westApril 13, 2009 at 6:01 AM

    Happy blogging...will keep on waiting for more here on this blog.

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  4. VinodApril 16, 2009 at 4:55 AM

    The only issue is how will you estimate batch process based application size for e.g. Rating engine in billing scenario. There are no users and there is no GUI - still you need to estimate size in FP and compare against the GUI based user applications for cost and productivity etc

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  5. YogeshApril 16, 2009 at 9:34 PM

    Vinod - when I say business users, i do not necessarily mean, the GUI users. These are Business SMEs who should be driving requirements. Now the billing process (batch process which generates the bills and applies rating/discounts etc.) will be a requirement given by these SMEs only. So they will understand what business data and transations are required to run such processes. So FP can definitely be used for such processes as well.

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  6. Tanweer ManiyarNovember 25, 2009 at 6:10 AM

    Hi Yogesh, very good and spot on write-up on FP. We normally face this issue on UII because MSI SN / SSO are algorithm heavy functions. Other drawback of FP is it is scalable in proportion to tables, input-output fields etc. Though it places upper cap after certain number of DETs & FTRs, but I think this very limitation is a drawback.

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