Effectiveness – How well the user achieves the goals they set out to achieve using the system (process).
Efficiency – The resources consumed in order to achieve their goals.In Software field, these terms are primarily used to indicate the effort put in to develop the Software and How much is customer satisfied with the product.
Effectiveness signifies how well the customer requirements have been met i.e. does the final product provides the solution to the Customer problem effectively.

Efficiency is something, which is internal to the Organization that produced the Software product. It is basically- how efficiently the available resources (time, hardware, personnel, expertise etc.) were utilized to create the Software product.


Thus, Effectiveness of Software is a measure of Customer response on meeting product’s requirements and Efficiency is a measure of optimum utilization of resources to create the Software product.

Effective – producing a powerful effect
Efficient – producing results with little wasted effort

Example:
James efficiently made the calls he had wanted to make. Robert didn’t make the calls he had planned to make, but effectively met his sales quota by profiting from a chance encounter with a business acquaintance.

Key Point:When you’re effective, you are able to accomplish the worthwhile goal you’ve chosen. When you’re efficient, you quickly carry out actions. You won’t be effective, however, unless those actions result in your achieving a meaningful goal.

Test Effectiveness = ((Defects removed in a phase) / (Defect injected + Defect escaped)) * 100
Test Efficiency = (Test Defects / (Test Defects + Acceptance Defects)) * 100

The Test defects = Unit + Integration + System defects
Acceptance Defects = Bugs found by the customer