The three-point estimation technique is used in management and information systems applications for the construction of an approximate probability distribution representing the outcome of future events, based on very limited information.
Based on the assumption that a PERT distribution governs the data, several estimates are possible.
These values are used to calculate an E value for the estimate and a standard deviation (SD) as L-estimators, where: E is a weighted average which takes into account both the most optimistic and most pessimistic estimates provided.
It differs from the double-triangular by its simple triangular shape and by the property that the mode does not have to coincide with the median.
To produce a project estimate the project manager: The E and SD values are then used to convert the project time estimates to confidence intervals as follows: These confidence interval estimates assume that the data from all of the tasks combine to be approximately normal (see asymptotic normality).