The fact that planning estimates represent a probability distribution is well known and there is an established process (PERT)[1] for estimating the expected time of a set of estimates - essentially instead of asking for a single &#x27;most likely&#x27; estimate you should as well explicitly walk through some of the risks around this and the ask for an &#x27;optimistic&#x27; estimate (which is frequently very similar to the initial estimate) and a &#x27;pessimistic&#x27; estimate (which is frequently much larger) - given:<p><pre><code>  m = &#x27;most likely&#x27; time
  o = &#x27;optimistic&#x27; time
  p = &#x27;pessimistic&#x27; time 
</code></pre>
You can then estimate the expected time &#x27;e&#x27; by modelling a triangular distribution based on these and sum the estimates on the critical path.<p><pre><code>  e = ∑(oi + 4mi + pi)&#x2F;6
</code></pre>
This is actually a very useful technique but sadly is done very infrequently (probably because it usually comes up with an number that people don&#x27;t want to hear - but is usually much more realistic).<p>[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Program_evaluation_and_review_technique" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Program_evaluation_and_review_...</a><p>The program (or project) evaluation and review technique, commonly abbreviated PERT, is a statistical tool, used in project management, which was designed to analyze and represent the tasks involved in completing a given project. First developed by the United States Navy in the 1950s, it is commonly used in conjunction with the critical path method (CPM).