What is the implementation strategy that generally involves the lowest cost?

The choice of "Big Bang" as the implementation strategy that typically involves the lowest cost can be understood through its approach to deployment. In a Big Bang implementation, all components of a system go live at once, which means that everything is switched over in a single, concentrated effort. This can lead to reduced costs in several ways:

1. Resource Allocation: Since all parts of the system are launched simultaneously, there is often less need for extended project management and monitoring. Fewer resources are required over a longer period when everything is done at once.

2. Reduced Overlapping Costs: With systems running in parallel, as seen in other methods like Parallel Run or Incremental Rollout, there are often ongoing costs associated with maintaining multiple systems at the same time. The Big Bang approach minimizes this by eliminating the dual-system maintenance period.

3. Simplified Training: Training can be concentrated on a one-time rollout, rather than staggered sessions required across multiple phases, which can economize valuable time and training resources.

While there may be risks and potential challenges associated with the Big Bang approach, in terms of initial financial expenditure, it generally results in lower costs compared to strategies that require ongoing coordination, phased implementations, or parallel operations.