Is Resource Loading Linear? RRS feed

  • Question

  • Hey all,

    I have a resource that performs 1500% work a day (15 man crew), they will work for 50 days.  I have about 65 tasks that need to be done, I've set the priority and relationships and loaded each task with the resource, which gives me a perfectly loaded resource schedule of 150 hours per day for 50 days.  

    Then I try to muck it up with reality and I start changing the durations (fixed work) to more realistic values, IE Task A (20hrs) is not going to finish in 1.3 hrs, so I set it to 2 days, it adjusts the resource usage perfectly (at a linear usage per day).  Unfortunately, doing this it's almost impossible to get exactly 150hrs used per day for 50 days, so my schedule constantly keeps pushing out to the right and I end up mucking with durations and loading for hours upon hours.

    I feel I'm close to having the understanding required to beat this, but I'm missing something.  My fixed values are Work, the 50 day timeframe, and the resources available.  Is there an easier way to make sure that all 150hrs of work are applied each day?  If resource usage adds up to 120hrs, can't MSP just assign 30 hrs to the next task in line?

    Thanks for reading, any advice would be appreciated!


    Friday, June 19, 2015 7:13 PM

All replies

  • Bergman99,

    Why do you set the priority?
    If you have just the one resource with max units = 1500% you won't be able to level anyway, and that's what priority is for.

    I am guessing that you start off with all 65 tasks having duration = 1 day, the default (or is it 1.3 days?).
    Then you assign the single resource to each of the 65 tasks at sufficient units, different for each task, so that the total work for all tasks is 50 days x 150 hours/day = 7500 hours.

    Also guessing, however, at this stage you have all the 1 day tasks linked but the total duration is not 50 days. So this is why you start changing the durations, in order to make the overall duration 50 days. I can't see what the task durations end up being or how the tasks are linked (maybe some overlap) but this seems possible.
    But are you also trying to make the overall daily rate of work be 150 hours/day?

    If you can clear this up I think we can have a perfect solution. Basically, you are starting at the wrong end. You should estimate the durations first, get the predecessors/successors right, then assign the resource, then level. Then all of the rest, the work and daily rate etc are all output, not input. Also, you are juggling too many balls at once. It looks like you are starting to plan "top down" and then switching to "bottom up", and this leads to going around in circles. Also, it is always better and easier to make 15 individual resources instead of one resource which represents the whole crew. This should only be done when the whole crew is always assigned to every task, such as when two carpenters always work together.

    Friday, June 19, 2015 10:49 PM
  • Thanks for the response Trevor,

    I had set the priority so that the "15 person crew" would automatically head to the next activity in line based on the relationships/priority.  

    As you guessed, the daily rate of work is 150 hours, whether or not any work gets done. Work is my fixed value, the activities are supposed to take X amount of hours for each, which I'm trying to break the hours down into a logical time frame with however many workers would be practical.  Activity A is 400 hrs, 4 people for 10 days, so on so forth. There is 50 working days to the schedule and we intend on having 15 workers for the 50 days, to meet our 7500 manhour budget.  

    So I've taken your advice and split the 1500% worker and made 15 individual resources, now I am assigning them to individual tasks.  I'm having trouble keeping track of what resources are free for an activity.  Is there a particular view that makes short work out of this?

    Monday, June 22, 2015 6:03 PM
  • You don't need to keep track of their availability. Simply assign them in the necessary numbers to the tasks until they become over-allocated, then assign someone else. If you have enough people you may be able to avoid over-allocation entirely, depending on the sequencing and how the tasks are linked as predecessors/successors and how much overlap there is between the tasks.
    However, some over-allocation is more or less inevitable. This is fixed with leveling.
    Some more information which is relevant to your problem and would help the answer is:

    Are all of the tasks of the same kind?
    Are all of the resources of the same kind?
    Does it matter which of the resources are assigned to which task(s)?
    What is the duration estimate of each of the 65 tasks?
    How many of the 15 available people is assigned to each task?
    Are the tasks all linked into a network with predecessors and successors and what does the resulting Gantt chart look like?

    Wednesday, June 24, 2015 4:16 AM