Big Bang or Phased Implementation

One of the challenging decision for an ERP implementation is the implementation approach; should you take the big bang approach and get it done sooner, or should you slowly phase in the new processes and technology over a period of time. There are several schools of thought regarding application deployment. Some favor phased deployment, while other business/operations require a big-bang approach.

Phased Implementation: In this type of an implementation smaller group of users or specific sites/locations or selected processes/functionalities are deployed at a time. Minimal disruption to the production environment is a key consideration here. Any performance issues that occur can be quickly isolated and rectified without any large-scale disruption to the wider user population. This approach allows for a staggered training, so you potentially have fewer users impacted at a given time. However, this could potentially require keeping two separate systems running, hence more system support requirements including ongoing maintenance costs. This may also lead to the issue of data correlation, where there is a need to cross-reference data across two systems, and may add unnecessary complexity into the system.

Big-Bang Implementation: With this approach the application is deployed in a single go; all users concurrently cut over to the new system. This imposes potential large-scale disruption to production environment. Performance issues may result in large-scale disruptions to entire user population. This approach requires mass training to get all users trained around the same time. The good news is that there is only single system running at one time, so there is no need for additional system support unlike the phased approach, hence low maintenance costs compared to the phased approach. This also helps organization get to the end state sooner and enable faster realization of the ROI. Big-bang implementations must ensure comprehensive planning and coordination in the contingency/risk planning process.

Both approaches have their clear pros and cons. It is important to find a balance between both that works best for your organization. Implementation schedules need to be aggressive, but not to the extent that they cause you to overlook important details or make incomplete decisions and testing. Failed implementations can cause serious damage to your organization. You must spend a good amount of time to analyze the right approach that supports your business within acceptable risk tolerance limits.

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