# Man hours

Copper Contributor

# Man hours

Will project calculate man hours based on project timeline?

5 Replies

# Re: Man hours

Innpower77 -- If you assign resources to tasks, then yes. You will need to initially enter a Duration value for each task and you will need to enter a Units value for each resource that you assign to the task. The Units value is a percentage number that indicates whether the resource will work full time on the task (Units value of 100%) or part-time on the task (Units value less than 100%). When you assign a resource to a task with a Duration value entered for the task and a Units value for the resource, Microsoft Project will calculate the Work value. The Work value represents the man hours for that task. Hope this helps.

# Re: Man hours

Well, yes and no. Let's say you have a simple project with a timeline of one month. If a single resource is assigned at 100% (i.e. full time), Project will calculate 160 hours of work. If a single resource is assigned at 50% (i.e. half time), Project will calculate 80 hours of work.

However, if you simply have a timeline describing a total span of time for one or more tasks, Project will not assume that represents a given number of man hours. There are too factors that play into a plan to give a simple answer to timeline versus man hours.

If you can explain in more detail what you are trying to accomplish, then we can be of further help.

John

# Re: Man hours

Thank you! So we have numerous upcoming projects (as well as current ongoing projects)  with start and finish dates, so we want all those on a schedule, trying to determine how many man hours we will need for projects, ultimately being able to determine if we need to hire more people. I hope that makes sense

# Re: Man hours

It sounds like you are approaching this at too high a level since you are talking about "projects". Normally a project is a collection of activities (tasks) linked together in a logical sequence to achieve an end goal. If all you have at this point is the start and desired finish of a "project" (i.e. single timeline), then the best you can do for a manpower estimate is to compare it with similar projects that were completed and perhaps apply educated guess adjustment factors.

In order to get a better and more realistic manpower estimate, each project must be broken down into the sequence of tasks mentioned above. Given that, if you know the estimated time span (duration) for each task and the estimated manhours to accomplish each task, you could set Project's task type to "fixed duration", enter the duration and work and then assign an arbitrary resource. Project will calculate the required number of resources required. for example, in the following example the "project" consists of four tasks in logical sequence, each with an estimated duration and work content. When the "people" resource is assigned, Project calculates the assignment level required. The assignment level is shown in the Resource Name field as a percentage of a full time work resource. The level of course varies over the total project timeline but in this example, 2 people will be needed for the last task.

This is a very simplified example to what is a complex process but it might be useful as a first draft approach.

John

# Re: Man hours

To build upon what John has said; people often ask "to what level should the tasks be broken down to?". A deceptively simple answer is to consider the resources that will need to work on each task. For example to produce a specification you could have a task "produce specification" however I would suggest this would be one level above what is ideal as you will have the Author producing the spec, working with maybe a user and then a much wider group reviewing it and a smaller group signing it off. If you have a single task it will make the reviewers and signatures look far busier than they really are. Thus it would be better to break it down into
1) Produce Draft Spec = Author + user
2) Review draft spec = cast of thousands reviewing it
3) Modify spec = Author and user
4) Sign off specification = Sign off athories.
In this way you can show that the reviewing team are not busy for the whole of the time it takes to produce, review, modify and sign off.
Then you can go about assigning the allocation - so the review stage will only take each reviewer say 0.5 days but they need to be allowed a week to all get around to doing it; so each reviewer is allocated at 10% of the 5-day duration.
Once you have this level of detail in the plan MS Project will be able to give you an accurate view of the levels of each resource that you need. However, you do then need to look at the resulting detail with a realistic eye as whilst you may only need the technical author for say 3 weeks over a 2 month period (for instance) you will probably have to recruit or pay for them for the whole time period unless you can cost share with other projects.