The PRIMARY reason for using quantitative criteria in developing business cases for IT projects is to:

Quantitative criteria, such as ROI, NPV, or cost-benefit ratios, provide a clear, measurable basis for predicting project outcomes. By setting these metrics upfront in the business case, an organization can effectively assess whether the project achieved its intended financial and operational returns after it is implemented, facilitating objective performance evaluation.

While benchmarking can be part of project planning, the primary reason for using quantitative criteria in a business case is to measure the project's own success against its stated objectives, not solely for external comparison.

Learning lessons from past errors is important for continuous improvement, but it's a separate activity from the primary purpose of defining quantitative criteria in a new business case.

Applying corporate standards is about compliance and consistency, which is different from using quantitative metrics to specifically evaluate returns after a project is completed.