Percentages by opinion
The basis and uncertainty of reported progress affect how the information can be interpreted.
General contractors, subcontractors and construction managers

For contractors
Progress monitoring is the discipline of checking the reported position against the physical one, period by period, so that variance is caught while there is still time to respond to it.
Progress, production rates and forecasts may provide different information about a project. Trends, measurement changes and possible responses are considered in the circumstances rather than through a fixed hierarchy of indicators.
Progress and payment information may be evaluated using measures suited to the contract and work. Physical quantities, reported percentages, milestones and other evidence have uses and limitations; differences are assessed in their contractual context.
Differences between reported and actual progress can arise from measurement conventions, incomplete work, estimates, errors or unsupported entries. Monitoring documents those differences and examines their effect on forecasts.
Contractor and owner records provide different views of the same work. Their usefulness rests on timing, support and consistency with the rest of the record. The author’s identity alone does not settle the weight of the information.

Possible assignment considerations
Agree what counts as progress for each kind of work before measuring any of it, so the series stays comparable from period to period.
Physical observation against the schedule and the drawings, the step that catches the difference between delivered, installed and complete.
Actual production rates set against the rates the baseline assumed, and actual progress against the current schedule rather than the original one.
The gap, its direction, and what is driving it, in a form the project can act on this month and a reader can rely on later.
Considerations and limitations
The basis and uncertainty of reported progress affect how the information can be interpreted.
Summary activities that roll detailed activities into one longer bar can hide slipping work or low production rates that show up only in the detailed activities.
Contractor and owner records provide different views of the same work. Their usefulness rests on timing, support and consistency with the rest of the record. The author’s identity alone does not settle the weight of the information.
Construction Progress Monitoring
Also in this practice