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Project Management for R&D

Estimates and Hocus formula


There are three different concepts you need to keep in mind to improve your estimates and meet your deadlines in projects:

  • Peoples tendency to either be an optimist or a pessimist

  • Task time variation

  • Student syndrome


People's tendency

Our "How long is a piece of string"- exercise shows that the distribution of individual estimates is not a normal distribution. Actual project experience also indicates that various people's estimates are not evenly distributed either. There is a tendency to underestimate rather than overestimate the time, cost, and resources in projects.


Task time variation

The curve shows the frequency distribution of human activities. Sometimes things go wrong, and some things will go wrong! For example, how long time does it take to get to work every morning? Some days it goes like clockwork, and travel time is short, but unfortunately, that doesn't happen every day. Sometimes traffic is terrible, and your traveling time becomes much longer — same in projects. Sometimes we run into trouble, and things take an unexpectedly long time to complete.  


Student syndrome

Activities within a project tend to take the time they are allocated. Many of us put things off until later, especially in today's working climate where we don't have just one deadline to meet, but many. Priority is given to what is most urgent because the system penalizes delays but doesn't reward being ahead of schedule.


Most people underestimate the time or cost in a project

A few overestimate

Guidelines to improve estimates:

  • Avoid individual estimates and have multiple people make estimates. Use the mean values.

  • Don't only estimate the probable value but also estimate an optimistic and pessimistic value.

  • Use the Hocus formula to calculate your final estimate

  • Every estimate is always associated with a level of uncertainty. The optimistic deadline has a lower probability of being met than the pessimistic. Be open and show your probabilities.  


Final estimate = 1*optimistic + 2*pessimistic + 3*probable / divided by 6


Of course, the formula's name is not Hocus, but we like the name because it's a little bit like magic.

Preferably you can use our Excel template for making your estimates. It can be downloaded on the link below.

Add your estimates to the template:

​If you used the Excel file you get estimates in two dimensions:

  • vertical per project dimension

  • horisontal per stage or time period.

You may also need to consider what estimates that are going to be displayed in the template:

  • probable

  • pessimistic

  • optimistic

  • hocus.

Depending on the purpose different estimates may have to be used in a project. Maybe the probable in your goal statement and the pessimistic in a penalty clause in a contract. 

Estimates per project dimension


Estimates per stage or time period

Guidelines to keep deadlines:

  • reward early delivery and verification of deliverables

  • if you plan and execute the project according to the deadline calculated using the Hocus formula or pessimistic value, the whole distribution will be shifted due to the student syndrome. To keep the probabilities intact, you need to plan and execute the project to achieve at least the probable value.

  • work with several deadlines simultaneously. The team has one deadline in the project plan when the product should be ready for launch, but the marketing department has a different deadline for starting the launch in their plan. If you both use the same deadline, the risk of being out of sync increases.

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