Depending on the type of contract and the revenue recognition method you use, you may need to account for changes in different ways. For instance, when dealing with fixed-price contracts, if the percentage-of-completion method is used, you need to adjust the estimated total costs and revenues based on the changes and recalculate the percentage of completion and the revenue recognized to date. On the other hand, if you use the completed-contract method, all revenue recognition must be deferred until the project is completed or substantially completed. For time-and-materials contracts, if you use the output method, you need to measure the revenue based on the units delivered or milestones achieved, and adjust it accordingly if there are changes in the output. If you employ the input method, you need to measure the revenue based on costs incurred or hours worked, and adjust it according to any changes in input. Lastly, with cost-plus contracts, if you use cost-recovery method, recognize revenue only to the extent of costs incurred and defer markup until project completion or substantial completion. If you use proportional-performance method, recognize revenue based on proportion of costs incurred to total estimated costs and include markup in recognized revenue.