Which of the following is NOT a method of estimating manpower needs?

Focus-based estimation is not commonly recognized as a method of estimating manpower needs compared to the other options listed.

Zero-based estimation involves starting from a "zero base" and evaluating each job function to determine the necessary manpower requirement from scratch, without assuming previous staffing levels. This method allows organizations to align manpower needs directly with current goals and objectives.

Incremental estimation, on the other hand, typically builds on existing staff numbers and adjusts them based on projected changes in workload or company growth. This method is often straightforward, as it examines past staffing levels and makes necessary additions or reductions based on anticipated changes.

Task-oriented estimation focuses on identifying specific tasks and activities that need to be staffed and calculating how many personnel are needed to complete these tasks effectively. This ensures that all tasks are accounted for and appropriately manned.

In contrast, focus-based estimation lacks the established framework and structured approach found in the other methods, making it less reliable as a method for estimating manpower needs.