Which of the following methods is considered the most accurate for estimating cost?

The Quantity Survey method is recognized as the most accurate for estimating costs due to its comprehensive approach. This method involves a detailed breakdown of all aspects of a project, including materials, labor, and overheads, which allows for precise calculations based on the actual quantities of work required. By examining each component individually, the Quantity Survey provides a highly accurate estimate reflective of the specific conditions and requirements of a project.

This method goes beyond general rules of thumb or historical averages and tailors the estimate to the unique elements of each project. It takes into account the current market prices, labor conditions, and material specifications, effectively reducing uncertainties in the cost predictions. Additionally, it often involves detailed measurements and assessments made by a qualified quantity surveyor who can identify potential cost savings or areas of concern.

In contrast, other methods like the Comparative Unit method evaluate costs based on similar projects, potentially leading to inaccuracies if the current project has different parameters. The Unit in Place method estimates costs on the basis of unit prices but may overlook specific site conditions. Trended historical cost relies on past data, which may not accurately reflect current market conditions. Hence, the Quantity Survey method stands out for its accuracy and specificity in cost estimation.