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Best Practice for Entering Task Estimates? RRS feed

  • Question

  • All,

    I know there may be different schools of thoughts on this and there may not be one universal method, but what do you consider to be the best practice for entering task estimates : by duration or work?

    I personally believe that a resource can more accurately judge how much 'uninterrupted effort' it will take he/she to complete a task if they were to do it 'heads down' with no distractions or breaks. The duration could then be calculated based on the resource(s) max units, project/task/resource calendars, task contorting, etc.  

     

    I'd be very curious to hear what anyone else's thoughts are on this and what you feel are the pros / cons of each method.

     

    Thanks

    Thursday, February 16, 2012 2:48 AM

Answers

  • Hi Joe,

    Welcome to this Microsoft Project forum:)

    I have said a number of times over the years that it is my view that estimating "How Long...?" depends more on the likely length of the task than the type of task engaged in.  For tasks that are less than a few days, then people will tend to answer in hours.  For more than a few days, people will naturally estimate in longer periods eg days or weeks.  I can't believe, in any project industry, a person will, say, it will take 234 man hours of work.  What I believe happens is that the same person will think that it will take him about 30 working days and then convert that to 240 manhours of Work or again for a 4 weeks estimate, convert to 160 manhours, all based on a 8-hour day and 5-day weeks.  So, why ask them to convert the Duration to Work when Project can do that for them?  Hence, I would always estimate in Duration (ie working time) and let Project calculate the Work (in manhours) necessary.

    FAQs, companion products and other useful Project information can be seen at this web address:  http://project.mvps.org/faqs.htm

    Hope this helps - please let us know how you get on :)

    Mike Glen
    MS Project MVP (97-11)
    See http://tinyurl.com/2xbhc for my free Project Tutorials


     

    Thursday, February 16, 2012 2:33 PM
    Moderator

All replies

  • Hi,

    All depends on the input available. Indeed, when the estimator (whoever) will normally estimate work (as is mostly the case in IT) then entering Work is best - why would you calculate duration by hand then let Project recalculate the Work you started from in the first place?

    Still, a big part of the projects I've been involved in have work done by resources not controlled by the project leader (you may be managing the building of a house, but the electricity is subcontracted to a specialized company for instance). Then Work doesn't have much sense, the resource will have to commit on delivery time, i.e. duration. For such projects or tasks in projects entering duration is logical and "best".

    In other words, enter in Project what is readily available!

    Greetings,


    Thursday, February 16, 2012 8:39 AM
    Moderator
  • The recommended method is the one that works best! For some peopel effort is easier to predict accurately, others number of working days (duration).

    You can only get better accuracy by doing Predict-Measure-Learn loop. No measurement, no learning no improvement. If measured result is consistently under-estimate, try predicting how long task will take if everything goes well then add on % chance the task will take twice as long. For example if estimate of work if everything goes well is 10h and there is a 20% chance of th task taking twice as long (20h) then add 20% to teh 10h: result work prediction of 12h.

    If estimates are always oer, adjust formula.


    Rod Gill

    The one and only Project VBA Book Rod Gill Project Management

    Thursday, February 16, 2012 9:26 AM
    Moderator
  • Hi Joe,

    Welcome to this Microsoft Project forum:)

    I have said a number of times over the years that it is my view that estimating "How Long...?" depends more on the likely length of the task than the type of task engaged in.  For tasks that are less than a few days, then people will tend to answer in hours.  For more than a few days, people will naturally estimate in longer periods eg days or weeks.  I can't believe, in any project industry, a person will, say, it will take 234 man hours of work.  What I believe happens is that the same person will think that it will take him about 30 working days and then convert that to 240 manhours of Work or again for a 4 weeks estimate, convert to 160 manhours, all based on a 8-hour day and 5-day weeks.  So, why ask them to convert the Duration to Work when Project can do that for them?  Hence, I would always estimate in Duration (ie working time) and let Project calculate the Work (in manhours) necessary.

    FAQs, companion products and other useful Project information can be seen at this web address:  http://project.mvps.org/faqs.htm

    Hope this helps - please let us know how you get on :)

    Mike Glen
    MS Project MVP (97-11)
    See http://tinyurl.com/2xbhc for my free Project Tutorials


     

    Thursday, February 16, 2012 2:33 PM
    Moderator