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# Units of work

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Polat Turan
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The fundamental formula for work is:

Work  = duration    x    number of assigned units to the task

So, for example:

Work = 5 days x 3 men = 15 man hours

So work is expressed as man hours (or equipment hours).... is that correct ? Or not?

I ask because in MS project it writes work as hours... not man hours....  that is why I am confused..... which one is correct?

## Replies

Raymund de Laza
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Hi Polat,

Work = 5 days x 3 men = 15 man hours , must be Read as 15 Man-Day.

If the Labors Work for 8 hrs per day then it Reads as 120 Man-Hours.

Hope this is Clear.

Rafael Davila
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BTW 5 days x 3 men = 15 man days not necessarily 15 man hours. If work hours are 1 hour per day/man then it would be 15 man-days. If 8 hours/day/resource it would be 5 days x 3 resources x 8 hours/day/resource =  120 resource hours.

Patrick Weaver
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Man hours is considered 'sexist' - the term 'work hours' or hours of effort or equipment hours have been substituted for gebder nutrality.

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Joined: 5 Feb 2001
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Polat,

in Spider Project there is activity Volume of work (1000 meters) and assigned resources productivity (meters per hour).

Duration is calculated as Volume divided by total productivity of assigned resources.

Resource hours are calculated as duration multiplied by resource quantity.

I expect that other experts will explain what is Work in other tools and why it is measured as duration.

I don't like it. Amount of work does not change when you replace resources but duration can change. And so more work or less work depends on resource assignments that is not logical.

Rafael Davila
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Polat,

I do not believe out of the box MS project has physical work field and production rate fields, you must figure out a way to tweak it. Maybe an attempt to fill the gap is through the use of physical % complete field but this is still incomplete data, volume of work is the missing link that makes production rates meaningful.

I suggest creating a UDF for; volume of work and production rate and make it transparent.  It will never be as functional as when these fields are integral part of the software logic but at least it is something.  When resource production rates are integral with your resource planning software it should be able to look for the best allocation of resources with different productivity.

I guess MSP was developed by accountants who can only think of work as work hours no matter if productive or not.  I am surprised they did not used the physics formula for work; work = force x distance.

Not all work can be measured if using physical progress, it is not always that easy; measuring programming progress can be one example.

As we say at home; faulty language faulty thinking.  You are right MSP glossary is faulty.

Rodel Marasigan
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Hi Polat,

Sorry, I don't understand what are you trying to achieved.

Polat Turan
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Rodel, ok lets forget MS project for a second. I gave it only as an example. In reality, work is the actual thing we need to do (lay 1000 meters of pipe). Not something in hours....

But in scheduling, it is represented as hours to simply indicate the amount of effort done by resources correct? So they should have said "amount of effort", instead of "work" correct? Because the scheduling program calculates it by work (amount of effort) = duration x number of resources assigned to it.... as in the formula I wrote

Polat Turan
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Rodel, ok lets forget MS project for a second. I gave it only as an example. In reality, work is the actual thing we need to do (lay 1000 meters of pipe). Not something in hours....

But in scheduling, it is represented as hours to simply indicate the amount of effort done by resources correct? So they should have said "amount of effort", instead of "work" and it is in hours correct? Because the scheduling program calculates it by work (amount of effort) = duration x number of resources assigned to it....

So for example lets say we have 100 meters of pipe to lay. This is the work in reality. But in scheduling the work is represented as work = duration x number of assigned resources. So if the task continued 5 days and 4 labor worked on it, then the work is 4x5 = 20 hours. And lets say 1 man-hour is rated at \$40. So the actual labor cost of laying the pipe would be 20x40=\$800. And if 1 meter of pipe costs \$10, then the cost of material is \$10x100 = \$1000. So the actual cost (AC) that we will use in EVA will be: \$800 + \$1000 = \$1800. Correct?

And if during estimating stage we had planned work as 5 days x 5 labor, it means we had planned it as 25 man hours. This means, we had planned 25x40=\$1000 for labor. Material is the same so our planned value PV was \$1000 +\$1000 = \$2000 correct? so the cost variance would be \$1800-\$2000 = -200 which means we are under budget.

And in all this, work is in hours

Rafael Davila
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Rodel Marasigan
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Your fundamental formula is not correct. You can enter the unit without the resouces. Please read my post. Material unit of measure will be shown once defined and assigned to task. See below:

msproject_resource_assignment.jpg

The default is hours because the resource default is work. Please note that unit of measure of materials cannot added to hours therefore unit is not shown unless it is define.

Polat Turan
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Thanks Zoltan I understand what you say and agree with you, but then why is the fundamental work formula as follows:

Work = duration x number of assigned resources

.....this makes work as duration x labor = manhours.... not how many light fxtures we install

Zoltan Palffy
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work is something that has to get done. In the construction world most work can be measured in units or quantity to install

let's take light fixtures as an example you create an activity to install light fixtures there is an specific number of light fixtures for that activity in may be in a particualr area or room. So you need to know the Quantity of light fixtures before you can say how many manhours hours it is going to take and how many men you want to use to install them.

Rodel Marasigan
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Hi Polat,

Work in MS Project = hours not manhour because it can be an equipment hours or labor hours. As I explained earlier, there is only 3 types of resource in MS Project:

1. Work (labour or equipment)

2. Material

3. Cost (Expenses)

If you define a resource as Material and assigned it to Task the Work will show the unit of measure (Material Label) enter on the Resource Sheet.

Polat Turan
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Thanks Rodel,

I am not sure if I understand all you said but I think you are describing what MS project does. My question is though, this: Is work expressed in hours or man hours, as in the fundamental formula I wrote?

Polat Turan
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Thanks Vladimir I think the same way, but then what about the formula itself? Per that we have man hours. So which one is right?

Rodel Marasigan
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Hi Polat,

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Correct way to measure the work is physical units (cubic meters, tons, etc.). With the same man hours different volume of work can be done.