Final answer:
The principal advantage of the completed-contract method is that reported revenue is based on final results rather than estimates of unperformed work.
Step-by-step explanation:
The principal advantage of the completed-contract method is that reported revenue is based on final results rather than estimates of unperformed work. The completed-contract method is a method of accounting for long-term construction contracts where revenue and expenses are recognized only when the project is completed. This method provides a more accurate representation of the financial results of a contract that extends into multiple accounting periods.