Difference ERP vs non-ERP

•          Non-ERP: make your use cases etc. Estimate on a use case basis

•          ERP: basic functionality already available, making usecases not seen as useful…

ERP: use available components as metric objects

How?

What is available at the end of Inception phase?

•          Highlevel Business Process

•          Highlevel Business Requirements

•          Global Impact Analysis                

•          Use Case Model

•          Architecture Description

And because you chose ERP

All documentation/experience/knowledge of that ERP

Proposal for Metric Objects in ERP projects

Classify business process

–        New: New business process (not implemented in ERP before)

–        Modified: Business process implemented in ERP but with modifications

–        Re-use: Business process implemented in ERP without processmodifications

Classify Standard & Custom components

–        New: components to be developed because COTS application does not provide for required functionality

–        Modified: components to be modified because COTS application already contains (standard components but these do not entirely meet the requirements

–        Re-use: pre-existing software will be used, but needs to be tested and integrated with new and modified components

Detail level

Classification business process

–        Clear link to process-model tool must be used

Classification COTS components

–        ‘Chunk of functionality’ within ERP-module: Receipts, Payments etc

–        Independent functioning customization: 1 Interface, 1 report

•      Detail too low: ERP module Accounts Payable

•      Detail too high: Individual form, parameter for report

Find Agreement on classification

•          Classification done individually by

–        Business keyusers

–        Supplier – application consultants

–        Supplier – customization consultant

–        Testconsultant

•          Together agree on complexity per businessprocess

–        Per businessprocess count

•      Nr of new components

•      Nr of reused components

•      Nr of modified components

–        Result is: estimation points. A number (like function points) which gives:

•      indication of expected effort needed for a businessprocesses

•      Indication of complexity of a businessprocess in relation to the other businessprocess (relative weight).

How to use the results to refine estimates?

First use own experience on how many hours per point

Then:

Ask supplier to report (weekly) on hours spent per business process in elaboration phase.

This gives an indication of the hours needed in elaboration phase per process identified in the impact analysis.

Supplierdeliverables in elaboration phase can be linked to businessprocesses from the impact analysis. Therefore reporting on hours spent per process should not be a problem.

Future projects can be used to refine this.

Tips

•          Do not treat it as a science

•          Try to find the most suited variable for your situation

•          Use more then one estimating technique

•          Just do it!