In the articles that make up this series, we shall examine a framework for developing duration estimates for any type of task. This will be based upon the general expression for durations, expressed in terms of the major factors influencing its calculation. The equation, which we shall derive in the second article, has the form
This expression also allows us to develop a uniform process, a step-by-step evaluation of these factors, allowing us to arrive at a robust and defensible value for the duration. The major difficulty in all of duration estimating is dealing with tasks whose 'volume', a measure we shall use to summarise its size, complexity and quality attributes, is not easily quantified. This is characteristic of tasks involving creative activities such as design, writing, drawing, coding, researching, analysing or calculating. We shall deal with this challenge in the fourth of the series of articles found here.
In the fifth and final article we shall note that any duration calculation, whether involving quantifiable tasks or not, can represent at best some kind of central value such as the mean (average value), the mode (most likely value) or the median (value representing the 50th percentile). None of these are ultimately satisfactory and, at least for vital tasks, (i.e. those sitting on the critical path,) some type of simulation will be required to glean a true sense of the probabilities of achieving values across the possible range. This will allow us to assess the likelihood of a task's duration being less than or equal any specified figure.
