Calculate 'Optimistic' & 'Pessimistic' Durations

[DonD]

Is there a way that Project can calculate the Duration for a task (and hence
for the entire work plan) based on the 'Optimistic' Work estimates for each
of the resources assigned to the task?

It as though I'd like to replicate what is currently happening with the Work
& Duration fields.

Hypothetically the 'Optimistic' Work estimate could be stored in the Number1
field, and the 'Optimistic' Duration could be stored in the Duration1 field.

 

[Steve House [Project MVP]]

Take a look at the help discussion on the PERT tools. It'l do exactly
what I think you're looking for.

 

[DonD]

Thanks for the reply, Steve.

Can you give me a pointer to the Help tools you mentioned?

Also, will the Duration calculation use the PERT formula (O + 4ML + P)/6, or
will it use the 'standard' formula that is associated with the Duration
field? Also, is the solution extensible so it would calculate both the
Optimistic and Pessimistic durations?

Take a look at the help discussion on the PERT tools. It'l do exactly
what I think you're looking for.

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

Is there a way that Project can calculate the Duration for a task (and hence
for the entire work plan) based on the 'Optimistic' Work estimates for each
of the resources assigned to the task?

It as though I'd like to replicate what is currently happening with the Work
& Duration fields.

Hypothetically the 'Optimistic' Work estimate could be stored in the Number1
field, and the 'Optimistic' Duration could be stored in the Duration1 field.

 

[davegb]

Thanks for the reply, Steve.

Can you give me a pointer to the Help tools you mentioned?

Also, will the Duration calculation use the PERT formula (O + 4ML + P)/6, or
will it use the 'standard' formula that is associated with the Duration
field? Also, is the solution extensible so it would calculate both the
Optimistic and Pessimistic durations?

I'm not sure I understand what you're trying to do. If the O and P
durations are calculated based on the ML (or E, in Project), then the
calculated duration, normally called "Expected", except in Project,
would be calculated without actually calculating the others. Is it just
that you want to be able to have and "O" Gantt, a "P" Gantt, and an "E"
Gantt? How you should do this depends on why you're doing this. Can you
elaborate?

Take a look at the help discussion on the PERT tools. It'l do exactly
what I think you're looking for.

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

Is there a way that Project can calculate the Duration for a task (and hence
for the entire work plan) based on the 'Optimistic' Work estimates for each
of the resources assigned to the task?

It as though I'd like to replicate what is currently happening with the Work
& Duration fields.

Hypothetically the 'Optimistic' Work estimate could be stored in the Number1
field, and the 'Optimistic' Duration could be stored in the Duration1 field.

 

[Steve House [Project MVP]]

Just look in the help index for PERT. When you display the PERT toolbar for
each task it will give you a form to enter the Optomistic, Pessemistic, and
Most Likely values. Hitting calculate uses the formula (O+4ML+P)/6 (you can
change the weighting if you like) to compute the Expected duration which is
what appears in the plain Duiration field. The three input values appear in
Duration 1, Duration 2, and Duration 3. You can choose to display any of
the 4 resulting Gantt charts.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs

Thanks for the reply, Steve.

Can you give me a pointer to the Help tools you mentioned?

Also, will the Duration calculation use the PERT formula (O + 4ML + P)/6,
or
will it use the 'standard' formula that is associated with the Duration
field? Also, is the solution extensible so it would calculate both the
Optimistic and Pessimistic durations?

Take a look at the help discussion on the PERT tools. It'l do exactly
what I think you're looking for.

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

Is there a way that Project can calculate the Duration for a task (and
hence
for the entire work plan) based on the 'Optimistic' Work estimates for
each
of the resources assigned to the task?

It as though I'd like to replicate what is currently happening with the
Work
& Duration fields.

Hypothetically the 'Optimistic' Work estimate could be stored in the
Number1
field, and the 'Optimistic' Duration could be stored in the Duration1
field.

 

[DonD]

Dave/Steve - Let me see if I can provide more rationale behind my request,
and I welcome your feedback to get me on the right track if my thinking has
gone astray.

The PERT Analysis capability relies on the O/ML/P *durations* to be entered,
but what I was striving to do was capture the work estimates per resource per
task (i.e., task 1 has resource A[75%] and resource B [25%], resource A's
3-point estimates for task 1 are 1hr/2hr/4hr, while resource B's estimates
are 2h/4h/9h) and have those durations calculated based on the resource
availability & allocation. The duration of the 'optimistic' hypothetical
work estimates might be 1d, but the ML duration is probably 2d and the
pessimistic is probably 3d. So it is possible, but onerous, to manually
figure out those durations per task, so I was wondering if the P & O
durations could be calculated based on the P & O work estimates.

Just look in the help index for PERT. When you display the PERT toolbar for
each task it will give you a form to enter the Optomistic, Pessemistic, and
Most Likely values. Hitting calculate uses the formula (O+4ML+P)/6 (you can
change the weighting if you like) to compute the Expected duration which is
what appears in the plain Duiration field. The three input values appear in
Duration 1, Duration 2, and Duration 3. You can choose to display any of
the 4 resulting Gantt charts.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs

Thanks for the reply, Steve.

Can you give me a pointer to the Help tools you mentioned?

Also, will the Duration calculation use the PERT formula (O + 4ML + P)/6,
or
will it use the 'standard' formula that is associated with the Duration
field? Also, is the solution extensible so it would calculate both the
Optimistic and Pessimistic durations?

Take a look at the help discussion on the PERT tools. It'l do exactly
what I think you're looking for.

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




On Mon, 10 Apr 2006 13:07:02 -0700, DonD

Is there a way that Project can calculate the Duration for a task (and
hence
for the entire work plan) based on the 'Optimistic' Work estimates for
each
of the resources assigned to the task?

It as though I'd like to replicate what is currently happening with the
Work
& Duration fields.

Hypothetically the 'Optimistic' Work estimate could be stored in the
Number1
field, and the 'Optimistic' Duration could be stored in the Duration1
field.

 

[DonD]

I forgot to mention in my most recent reply that my interest in doing this is
related to the Risk+ add-on. It wants the O, ML, P durations populated in
Duration1, Duration2, Duration3, from which it will produce the desired
histograms (e.g., Cost, Duration).

Thanks for the reply, Steve.

Can you give me a pointer to the Help tools you mentioned?

Also, will the Duration calculation use the PERT formula (O + 4ML + P)/6, or
will it use the 'standard' formula that is associated with the Duration
field? Also, is the solution extensible so it would calculate both the
Optimistic and Pessimistic durations?

I'm not sure I understand what you're trying to do. If the O and P
durations are calculated based on the ML (or E, in Project), then the
calculated duration, normally called "Expected", except in Project,
would be calculated without actually calculating the others. Is it just
that you want to be able to have and "O" Gantt, a "P" Gantt, and an "E"
Gantt? How you should do this depends on why you're doing this. Can you
elaborate?

Take a look at the help discussion on the PERT tools. It'l do exactly
what I think you're looking for.

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




On Mon, 10 Apr 2006 13:07:02 -0700, DonD

Is there a way that Project can calculate the Duration for a task (and hence
for the entire work plan) based on the 'Optimistic' Work estimates for each
of the resources assigned to the task?

It as though I'd like to replicate what is currently happening with the Work
& Duration fields.

Hypothetically the 'Optimistic' Work estimate could be stored in the Number1
field, and the 'Optimistic' Duration could be stored in the Duration1 field.

 

[davegb]

Dave/Steve - Let me see if I can provide more rationale behind my request,
and I welcome your feedback to get me on the right track if my thinking has
gone astray.

The PERT Analysis capability relies on the O/ML/P *durations* to be entered,
but what I was striving to do was capture the work estimates per resource per
task (i.e., task 1 has resource A[75%] and resource B [25%], resource A's
3-point estimates for task 1 are 1hr/2hr/4hr, while resource B's estimates
are 2h/4h/9h) and have those durations calculated based on the resource
availability & allocation. The duration of the 'optimistic' hypothetical
work estimates might be 1d, but the ML duration is probably 2d and the
pessimistic is probably 3d. So it is possible, but onerous, to manually
figure out those durations per task, so I was wondering if the P & O
durations could be calculated based on the P & O work estimates.

I understand what you're doing much better now. The only thing that
comes to mind is that you could use Project's calculation fields to
calculate a overall duration. You'd have to come up with the formulas
yourself, Project doesn't even recognize the concept of P, O, and ML
estimates for resource work effort. In fact, I've never heard of that
approach myself in 30 years of scheduling. Not that that invalidates
it.

I don't understand why you want to do the analysis you're asking about
here. Doesn't Risk + integrate with Project? I've never heard of this
kind of software requiring the user to do advanced Project
manipulations to give it the numbers it needs. Not very good
integration if it requires what you're asking for here. Are you sure
that Risk + needs 3 estimates of each resource's work effort? That
doesn't make much sense to me. Before you go ahead, make sure this is
what is required to use Risk +.
Hope this helps in your world.

Just look in the help index for PERT. When you display the PERT toolbar for
each task it will give you a form to enter the Optomistic, Pessemistic, and
Most Likely values. Hitting calculate uses the formula (O+4ML+P)/6 (you can
change the weighting if you like) to compute the Expected duration which is
what appears in the plain Duiration field. The three input values appear in
Duration 1, Duration 2, and Duration 3. You can choose to display any of
the 4 resulting Gantt charts.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs

Thanks for the reply, Steve.

Can you give me a pointer to the Help tools you mentioned?

Also, will the Duration calculation use the PERT formula (O + 4ML + P)/6,
or
will it use the 'standard' formula that is associated with the Duration
field? Also, is the solution extensible so it would calculate both the
Optimistic and Pessimistic durations?

:

Take a look at the help discussion on the PERT tools. It'l do exactly
what I think you're looking for.

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




On Mon, 10 Apr 2006 13:07:02 -0700, DonD

Is there a way that Project can calculate the Duration for a task (and
hence
for the entire work plan) based on the 'Optimistic' Work estimates for
each
of the resources assigned to the task?

It as though I'd like to replicate what is currently happening with the
Work
& Duration fields.

Hypothetically the 'Optimistic' Work estimate could be stored in the
Number1
field, and the 'Optimistic' Duration could be stored in the Duration1
field.

 

[DonD]

Dave/Steve - Let me see if I can provide more rationale behind my request,
and I welcome your feedback to get me on the right track if my thinking has
gone astray.

The PERT Analysis capability relies on the O/ML/P *durations* to be entered,
but what I was striving to do was capture the work estimates per resource per
task (i.e., task 1 has resource A[75%] and resource B [25%], resource A's
3-point estimates for task 1 are 1hr/2hr/4hr, while resource B's estimates
are 2h/4h/9h) and have those durations calculated based on the resource
availability & allocation. The duration of the 'optimistic' hypothetical
work estimates might be 1d, but the ML duration is probably 2d and the
pessimistic is probably 3d. So it is possible, but onerous, to manually
figure out those durations per task, so I was wondering if the P & O
durations could be calculated based on the P & O work estimates.

I understand what you're doing much better now. The only thing that
comes to mind is that you could use Project's calculation fields to
calculate a overall duration. You'd have to come up with the formulas
yourself, Project doesn't even recognize the concept of P, O, and ML
estimates for resource work effort. In fact, I've never heard of that
approach myself in 30 years of scheduling. Not that that invalidates
it.

I don't understand why you want to do the analysis you're asking about
here. Doesn't Risk + integrate with Project? I've never heard of this
kind of software requiring the user to do advanced Project
manipulations to give it the numbers it needs. Not very good
integration if it requires what you're asking for here. Are you sure
that Risk + needs 3 estimates of each resource's work effort? That
doesn't make much sense to me. Before you go ahead, make sure this is
what is required to use Risk +.
Hope this helps in your world.

Risk+ is nicely integrated into Project, but it is similar to the PERT
Analysis capability in that they both ask for me to enter the three DURATION
values (P, O, & ML). According to PM best practice materials, they encourage
us to allow the duration to be calculated based on the following task
details: a) work estimate per resource, b) resource availability (e.g.,
vacation), c) resource allocation (e.g., 75%). The calculation for the
'standard' DURATION field works great, but I was hoping there would be a way
to calculate the O & P DURATIONS using the O & P WORK estimates per resource
per task which would then feed into Risk+ to run the Monte Carlo simulations
resulting in the Cost & Duration histograms (among other outputs).

Risk+ stores the ML duration in Duration3, O duration in Duration1, and P
duration in Duration2. If I could figure out a way to populate those fields
with the calculated durations, based on the corresponding work estimates,
this would be a home run!

Just look in the help index for PERT. When you display the PERT toolbar for
each task it will give you a form to enter the Optomistic, Pessemistic, and
Most Likely values. Hitting calculate uses the formula (O+4ML+P)/6 (you can
change the weighting if you like) to compute the Expected duration which is
what appears in the plain Duiration field. The three input values appear in
Duration 1, Duration 2, and Duration 3. You can choose to display any of
the 4 resulting Gantt charts.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs

Thanks for the reply, Steve.

Can you give me a pointer to the Help tools you mentioned?

Also, will the Duration calculation use the PERT formula (O + 4ML + P)/6,
or
will it use the 'standard' formula that is associated with the Duration
field? Also, is the solution extensible so it would calculate both the
Optimistic and Pessimistic durations?

:

Take a look at the help discussion on the PERT tools. It'l do exactly
what I think you're looking for.

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




On Mon, 10 Apr 2006 13:07:02 -0700, DonD

Is there a way that Project can calculate the Duration for a task (and
hence
for the entire work plan) based on the 'Optimistic' Work estimates for
each
of the resources assigned to the task?

It as though I'd like to replicate what is currently happening with the
Work
& Duration fields.

Hypothetically the 'Optimistic' Work estimate could be stored in the
Number1
field, and the 'Optimistic' Duration could be stored in the Duration1
field.

 

[DonD]

In case anyone is on the edge of their seat waiting for the solution to this
question, I offer the following, somewhat un-elegant way to make this work.

I added six columns to the Task Usage view, one column for the Pessimistic
work estimate (Text10), Optimistic work estimate (Text11) & Most Likely work
estimate (Text12) and then a column for the Pessimistic duration
(Duration2), Optimistic duration (Duration1) and Most Likely duration
(Duration3) . I then fully expanded the work plan and executed the following
steps for each work estimate column:
- highlight and copy the entire column (e.g., ctrl-c)
- paste the values on the Work column
- recalculate the work plan (which updates the Duration column)
- highlight and copy the Duration column
- paste the values on the duration column corresponding to the source work
estimate.

I would typically process the Most Likely values last, since that would
leave the work plan in a state where the Work & Duration columns contain the
values that I'd want to publish to the project stakeholders.

Once the above steps are completed for each estimate, Risk+ will take those
duration columns and create the desired histograms (Cost, Duration, etc).
Those details enable the project to get a sense of the range of dates and
costs that the project is likely to encounter.

All told, the steps above took less than five minutes to perform, including
the creation of the histograms. The most time consuming part of the exercise
is obtaining the three-point estimates for each resource for each task. Once
that valuable exercise has been completed, the valuable statistics are then
readily created.

Hope that helps folks who have the luxury of being involved in projects
where the completion date is not pre-set (i.e., the completion date is
determined by the project team based on their understanding of how long the
discrete tasks will take).

Dave/Steve - Let me see if I can provide more rationale behind my request,
and I welcome your feedback to get me on the right track if my thinking has
gone astray.

The PERT Analysis capability relies on the O/ML/P *durations* to be entered,
but what I was striving to do was capture the work estimates per resource per
task (i.e., task 1 has resource A[75%] and resource B [25%], resource A's
3-point estimates for task 1 are 1hr/2hr/4hr, while resource B's estimates
are 2h/4h/9h) and have those durations calculated based on the resource
availability & allocation. The duration of the 'optimistic' hypothetical
work estimates might be 1d, but the ML duration is probably 2d and the
pessimistic is probably 3d. So it is possible, but onerous, to manually
figure out those durations per task, so I was wondering if the P & O
durations could be calculated based on the P & O work estimates.

I understand what you're doing much better now. The only thing that
comes to mind is that you could use Project's calculation fields to
calculate a overall duration. You'd have to come up with the formulas
yourself, Project doesn't even recognize the concept of P, O, and ML
estimates for resource work effort. In fact, I've never heard of that
approach myself in 30 years of scheduling. Not that that invalidates
it.

I don't understand why you want to do the analysis you're asking about
here. Doesn't Risk + integrate with Project? I've never heard of this
kind of software requiring the user to do advanced Project
manipulations to give it the numbers it needs. Not very good
integration if it requires what you're asking for here. Are you sure
that Risk + needs 3 estimates of each resource's work effort? That
doesn't make much sense to me. Before you go ahead, make sure this is
what is required to use Risk +.
Hope this helps in your world.

Risk+ is nicely integrated into Project, but it is similar to the PERT
Analysis capability in that they both ask for me to enter the three DURATION
values (P, O, & ML). According to PM best practice materials, they encourage
us to allow the duration to be calculated based on the following task
details: a) work estimate per resource, b) resource availability (e.g.,
vacation), c) resource allocation (e.g., 75%). The calculation for the
'standard' DURATION field works great, but I was hoping there would be a way
to calculate the O & P DURATIONS using the O & P WORK estimates per resource
per task which would then feed into Risk+ to run the Monte Carlo simulations
resulting in the Cost & Duration histograms (among other outputs).

Risk+ stores the ML duration in Duration3, O duration in Duration1, and P
duration in Duration2. If I could figure out a way to populate those fields
with the calculated durations, based on the corresponding work estimates,
this would be a home run!

Just look in the help index for PERT. When you display the PERT toolbar for
each task it will give you a form to enter the Optomistic, Pessemistic, and
Most Likely values. Hitting calculate uses the formula (O+4ML+P)/6 (you can
change the weighting if you like) to compute the Expected duration which is
what appears in the plain Duiration field. The three input values appear in
Duration 1, Duration 2, and Duration 3. You can choose to display any of
the 4 resulting Gantt charts.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs

Thanks for the reply, Steve.

Can you give me a pointer to the Help tools you mentioned?

Also, will the Duration calculation use the PERT formula (O + 4ML + P)/6,
or
will it use the 'standard' formula that is associated with the Duration
field? Also, is the solution extensible so it would calculate both the
Optimistic and Pessimistic durations?

:

Take a look at the help discussion on the PERT tools. It'l do exactly
what I think you're looking for.

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




On Mon, 10 Apr 2006 13:07:02 -0700, DonD

Is there a way that Project can calculate the Duration for a task (and
hence
for the entire work plan) based on the 'Optimistic' Work estimates for
each
of the resources assigned to the task?

It as though I'd like to replicate what is currently happening with the
Work
& Duration fields.

Hypothetically the 'Optimistic' Work estimate could be stored in the
Number1
field, and the 'Optimistic' Duration could be stored in the Duration1
field.