What should be put into a duration?

[aniki]

Hi friends,

I'm setting up a project. Before I went into MS Project,
I've got all tasks listed with estimated effort. Now, to
set up the project, should I simply put the estimated
efforts into Duration? Because once I put that into
Duration, Project set up the finish date by adding up all
the efforts. But the duration can actually be longer than
actual work 'cause I'll arrange training in the middle of
the project. It would be appreciated if any one could
answer my questions. Thanks a lot.

 

[Steve House [MVP]]

Well, if the training of the resources is needed so they can do the work
required to deliver the project, i.e., you have to teach people how to make
the widgets that they'll be creating later on in the project or how to use
the widgets your project creates once the project is over, then the training
is a part of the project's work and should be included in the schedule along
with the rest of the tasks. That being said, you should NOT simply transfer
your "effort" estimate over to the duration. They are in no way the same
thing! Instead, you need to estimate how long it will take you to get the
work done with the resources you plan to assign. Let's say I have to make
1000 widgets and 1 guy can make 10 per hour. My effort - 1000 widgets / 10
widgets per hour or 100 man-hours. We work an 8 hour workday. If I only
have 1 guy available, it will take 100 hours or about 12 days duration. But
if I can get 2 guys and have them both work on the widgets we'll get 2
man-hours worth of widgets, 20 widgets per hour, done for each hour of the
workday so we take 1000/20 per hour or 50 hours, about 6 days, to do the
same 1000 widgets. Etc Etc This is effort driven behavior. Or you might
have a case of a meeting that is expected to take 2 hours. That is actually
a duration estimate, not an effort estimate, to begin with. The
presentation will take the same length of time regardless of whether 2, 3,
10, or 25 of your resources attend but since you have to pay them all, the
effort is the number of resources times the length of the meeting.

Where have you entered your work estimate in your task list? If it's in the
Work column you're doing fine. Just assign the resources to their tasks and
project will calculate the task durations for you. If it's not in the Work
column, and that column isn't in the Gantt chart task list by default, you
have to add it to the table - you need to move them into there.

 

[John]

aniki,
The first thing to recognize is that Duration and Work are two separate
things. Duration is the time span during which the task will be
performed and it can be independent of the number of hours to actually
perform the task. Work on the other hand is normally the number of
manhours to actually perform the task. For example, a task may be
scheduled to be completed in a week but the resource(s) performing the
work may only need 30 hours to finish the task. The Duration then is 40
hours (assuming the default 8 hour workday and a 5 day workweek) and the
Work is set to 30 divided up among the resources assigned to the task.
If desired the task type can be set with a fixed duration (Project/Task
Information) to ensure the Duration remains independent from Work.

Hope this helps.
John

 

[aniki]

Thank you for the reply. Well, that's actually part of
where the problem came from. Unlike what you told me
below, I was doing according to what Project told me. So I
had to input Duration first, and then Project said Start
and Finish will come out automatically after I set up the
dependency between each task and mentioned nothing about
inputing Work.

I currently have 40 independent tasks and 5 resources. I
have set aside a separate training task for them to take
when then begin to do those 40 tasks. And the training
apply to all the tasks, so each resource will take more
training during their first task and less and less in
their following tasks as they know more about the basic
knowledge.

So am I doing it correctly? Or should I split the training
time into individual tasks? And once again, when setting
up the project, should I just input Work and Start and
ignore the Duration?

Thanks a lot,
aniki

 

[Steve House [MVP]]

A couple of things. First, if at all possible you should never, ever, enter
the start and/or end dates of the individual tasks. When you do so it
automatically establishes a constraint and it is rarely appropriate to the
task to have one. Of course, there occasionally are times where constraints
are legitimate - a piece of equipment might not be delivered by its supplier
before such and such a date, for example, and so the task to install it
should be constrained to start no earlier than the delivery date, but those
are relatively unusual circumstances compared to the total number of tasks
in a typical project. Ideally you input only ONE date, the Project Start
date (entered in the Project Information window from the Project menu) and
MSP calculates all the individual task start and end dates based on 1: the
durations of the tasks; 2: the logical relationships between the tasks, the
links; 3: the availability of the resources required to do the work. That's
why we use the software, to calculate those estimated schedule dates for us.

Work and Duration are replated mathematically by the percentage of the
resource's time he will be working, his assignment percentage, on the
instant task by the formula W=D*E. You can never have a task that violates
that fundamental identity. You can choose any two of those values to input
and Project will calculate the third for you. Generally speaking, you
usually assign a resource at 100% - if Bob is assigned to wax widgets I'm
going to expect him to devote his full attention to it until they are done.
So when I input the task I'm going to estimate its duration and let Project
calculate the Work. Later I may discover that Bob is tied up elsewhere for
part of his day those days or that I need him to be free some of his time to
work part of his day on some other task I have going on at the same time
that's can't be put off, so I might resduce his assignment to, say, 50%. In
that case, Project's default behavior is to recalculate the duration (in my
example, doubling it). Duration is estmated based on the anticipated
resoruces to be asigned, those resources are then assigned, and Project
calculates the Work (what you are calling "effort") for you.

An alternate way is to enter the tasks and leave their duration at the
default 1d? for now. Assign the resources at the percetnage that they
actually are available. Now enter the amount of work *each* resource will
do on the tasks in the Work column. Here you need to be careful because if
you have a task with 4 resources and you say the task requires 40 man-hours
of work, do you mean 40 hours for EACH resource or do you mean 10 hours for
each resoruces to make 40 hours TOTAL? When you supply the Work, Project
will then calculate the duration based on your work estimate.

The usual approach is to estimate duration and let Project calculate work,
simply because it's often an easier estimate to come up with. "We need to
wax 1000 widgets - last year we had a project where we waxed 100 and my
project archives tell me it took us a week with one guy working on it - if
I've only got one guy for it again this year, it'll probably take us about
10 weeks to do the required 1000 in this new project." So you enter in the
plan "Wax Widgets, Duration 10 weeks, BillyBob@100%" and let MSP calculate
the Work (in this case it'll come out to 400 man-hours if you are using the
default calendars).

IMHO, the training should be split out as individual tasks in their own
right. A task is a physical activity extending over a discrete time that
reults in ONE deliverable output. The entry state for the training is the
people required, students and instructor, for it are available. The
deliverable being constructed is a person who knows how to do XXX. The exit
state for the task is a set of trained individuals. They may USE that
training immediately or they may not use it for months. The resources
required for the training are the students and the instructor. The
resources required to apply the training are just the now-trained students
without the instructor being needed. If all the workers already had those
skills you could do the task itself without training them. Thus IMHO
training someone to polish fids and having them polish 100 fids are two
different tasks linked logically as training->doing because a: the
deliverables are different; b: the required resource skills sets are
different; and c: the time frames are different.

--
Steve House [MVP]
MS Project Trainer/Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs

 

[aniki]

Thank you Steve. That's very helpful to me. I just would
like to ask you one more thing. As I'm having 40
independent tasks (Summary Tasks) and I put 8 detailed
tasks into each of those 40 summary tasks. It really
doesn't matter which of those 40 gets done first, so I
didn't put dependency between the 40 tasks, but only
within the 8 detailed tasks. Now, I've assigned all my 5
resources to 40 of them. And Project seems to schedule the
detailed tasks randomly, so I'm having one resource doing
detailed task 1 of summary task 1 followed by task 1 of
summary task 5. As I would prefer each resource to
complete one summary task before doing the next one,
should I assign dependency to tasks belonged to the same
resouce? In that way, it would be difficult to maintenance
the dependency as I could rearrange the assignment later.

Thanks again,
aniki

 

[Mike Glen]

Hi Aniki,

In the Resource Levelling dialog, try changing the Levelling order to ID
Only. It should then ripple through each one in turn. If that isn't
satisfactory, then you coud try giving each batch of tasks a successively
lower priority and then level Priotity,Standard.

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

Mike Glen
MS Project MVP

 

[James G]

Hi Aniki,

You've just added additional detail about your situation....and it changes
everything!!

First...have you assigned resources on the Summary Task? If so, it would be
best to remove them and assign them on the detail tasks only.

You say that you would like one resource to complete "one Summary Task
before moving onto the next one". This implies that one resource will be
exclusively assigned to all of the detail tasks under that particular
summary. At the same time, you also say that you've applied all 5 resources
to all 40 summary tasks. Could you clarify this question: If you were to
assign resources to the detail tasks, would there be more than one resource
on each of the detail tasks?

You have stated a "preference" as to how the work should be executed. Here's
how:

1. You can force Project into completing all the tasks under one summary
before going onto the tasks of the next summary by applying a "Priority"
number to each task, and then use Resource Levelling. This is the recommended
method.

2. Another crude, but reasonably effective, way is by linking the individual
tasks that are relevant to each person, in the order that you would like them
to be done (Ok, I'm going to get shot by some of you.). However, if you start
doing the work out of sequence, you have to faff-around with amending the
logic links. This can be a real pain in the bum!

HTH.

James.G

 

[aniki]

Thanks a lot, after assigning priority to the summary
tasks, it does look better now. Actually leveling by ID
also helps. I still need trial time to figure out which
way is better. Another problem now is that even though
tasks are arranged more according to the sequence I want,
I do have some of the detailed tasks which only have a
Work of 8 hrs or 12 hrs spanning over more than two weeks
with some other detailed tasks belonged to other summary
tasks scheduled in the middle. Also two detailed tasks
(say both take 8 hrs each) belonged to different summary
tasks could begin at the same day and both finish on the
next day. Do I have to apply different priority to all the
detailed tasks to allow a detailed task to be completed
before beginning a new one? Is this a common thing when
using Project? If this is the only way, is there a quick
way to assign priority according to task ID because I have
hundreds of detailed tasks?

Thanks,
Aniki

 

[Mike Glen]

Hi Aniki,

I would level by ID and then examine those problem tasks that you described
and individually give them priorities to spread them how you want them.

Mike Glen
Project MVP