What is the best way to add buffer work in a project plan

[CP Jay]

Hi All,

What is the best or the most optimized way to add buffer resources in
an MPP?

Scenario -
Planning for a phase in the SDLC of a software project. Plan might look
like:
1. Phase 1 - 1 Jan - 31 Jan - 22 days - 176 hrs
1.1 Analysis - 1 Jan - 10 Jan - 7 days - 56 hrs
1.2 Design - 11 Jan - 13 Jan - 3 days - 24 hrs
1.3 Coding - 16 Jan - 20 Jan - 5 days - 40 hrs
1.4 Testing - 23 Jan - 31 Jan - 7 days - 56 hrs

In this scenario, i would like to make some provision for buffer
effort. I would like to add a Task 1.5 - Rework for 10 hour of work in
between 16 Jan - 31 Jan ( duration of 12 days )

What could be the best way to add this effort?

Postscripts:
1. The tasks are fixed unit tasks
2. One possible solution would be add a task as the next line item and
manually set the work to 10 hours and duration to 12 days with starting
day as 16 Jan,; and then allocate a resource.

Is there any other option or mehtodology?

Much Rgds
Jay

 

[Mike Glen]

Hi Jay,

Welcome to this Microsoft Project newsgroup

There are many ways that PMs create buffers. Your's is as good as any, but
you could assign resources to a lesser calendar than 5X8hrs per day, change
working hours, assign at less than 100%, add 10% to the Duration or Work of
each task, add padding tasks at the end or throughout....

What ever way you choose though, remember to never enter dates. Project is
designed for you the enter tasks and then the Durations and then the
prdcedence logic links and then resources and then level. Project will then
do as it's designed - calculate the dates for you and present to you a
practical schedule of dated based on you data inputs. Entering dates just
fills the project with constraints which will severely limit your
flexibility and give you a false impression of what is achievable.

FAQs, companion products and other useful Project information can be seen at
this web address: http://project.mvps.org/faqs.htm

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

Mike Glen
MS Project MVP
See http://tinyurl.com/2xbhc for Project Tutorials

 

[davegb]

Hi Jay,

Welcome to this Microsoft Project newsgroup

There are many ways that PMs create buffers. Your's is as good as any, but
you could assign resources to a lesser calendar than 5X8hrs per day, change
working hours, assign at less than 100%, add 10% to the Duration or Work of
each task, add padding tasks at the end or throughout....

What ever way you choose though, remember to never enter dates. Project is
designed for you the enter tasks and then the Durations and then the
prdcedence logic links and then resources and then level. Project will then
do as it's designed - calculate the dates for you and present to you a
practical schedule of dated based on you data inputs. Entering dates just
fills the project with constraints which will severely limit your
flexibility and give you a false impression of what is achievable.

FAQs, companion products and other useful Project information can be seen at
this web address: http://project.mvps.org/faqs.htm

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

Mike Glen
MS Project MVP
See http://tinyurl.com/2xbhc for Project Tutorials

As Mike said, there are a number of ways to add buffers. My experience
is to add as few as possible in larger increments, rather than add a
bunch of small ones. Particularly, I've found that adding it to
individual tasks to be self-defeating. If I add 10 or 20% duration to
each task, the resources working on that task see it as "their's" to
use. They inevitably do use it, and usually by starting 10 - 20% late
on the task, thus negating the purpose of the buffer. So I've ended up
adding buffer that gets used before the tasks start, and therefore only
extends the duration of the project without compensating for tasks that
took longer than planned. Doesn't work for me. Others may have
different experiences.

If the buffer is at the end of a major portion of the project, like
before a major milestone, I can usually convince the project team that
it's shared, and anyone who uses much of it up is taking it away from
the others. I find this a much greater incentive to not using it than
when I assign it to individual tasks. At the very least, it doesn't get
used up before they start work on the task!

Hope this helps in your world.

 

[Rod Gill]

My way is different again! I predict the duration or Work I expect the Task
to take if everything goes well. I then add the % chance of the Task taking
Twice as long. So, If I think that 10h of work is enough if everything goes
well and there is a 20% chance of the task taking 20h of work I schedule 12h
of work. In this way my estimates typically bracket reality and are either
under or over. You need to edit the formula so your predictions do bracket
what really happens.

I have contingency added as well for sections of the project where Risks may
happen (the fan gets dirty).

For each risk I estimate likely hours of extra work if the risk happens. I
multiply the extra work by the % chance of the risk happening and add the
result to the Contingency.

If I end up with too much contingency for the project's success, I do risk
mitigation to reduce risk to an acceptable contingency level. Contingency is
use it or lose it. If you need a week to do all work for the contingency
work with the resources you have available then you need to finish 1 week
early.

 

[CP Jay]

Hi Glen,

Thanks for the welcome and the multiple ways of adding buffer tasks !

IMHO, all of them sound good, but have their own drawbacks. For e.g. If
we allocate lesser calendar days or allocate lesser resources, it might
looks like a higher deviation on the metrics page. All at the same
time, the effort required for rework would become proportional with the
no. of tasks. This might not be the case always.

In the situation mentioned above, i am interested in adding a certain
amount of buffer time to a set of tasks - I have been depending on
padding tasks. That way, it shows explicitly in my status reports, all
of us aware of how much we are buffering within the team mgmt and the
consumption of such effort can be continuously monitored.

Please do share any further methodologies that you might have come
across.

And also, i agree with you more than hundred percent about the dates in
MPP. I am an ardent advocate of don't-change-date columns myself and
make that a point in all my knowledge sharing sessions - whatever
little i have the privilege of participating or conducting.

Thanks a lot and looking forward to more interactions!

 

[CP Jay]

Dave - i completely agree with you. In my reply to Mike, i think we
both have spoken the same thing, albeit in different languages!

Thank you for this suggestion - and please do share any further
technologies that you might come across!

Much Rgds
Jay

 

[CP Jay]

Hi Rod,

It is a really nice and elaborate way of adding buffer. But in my
situation, i would find the following cons for this approach:
1. I would want to differentiate between "variances from estimate" vis
a vis "planned buffer". An example might be in case of software coding
- The coding activity could be estimated for 40 hours and if the team
member takes 50 hours for this work item, then this should be tracked
as a variance against estimate. After coding would come testing. In
case of the testing producing any defects, then the team member would
have to spend effort on rework on the code piece. This work item of
rework is what i want to add as a buffer effort in the plan. I might or
might not use up this work effort, but this should be tracked
seperately from the extra hours used for coding.

The problem in this case would be that allocation of this effort, more
often than not cannot be planned as spending so 8 hours on this day -
this could be spread out across multiple days with the resource
spending some hours every day or something like that...

I hope my description was clear...

 

[CP Jay]

Hi Rod,

It is a really nice and elaborate way of adding buffer. But in my
situation, i would find the following cons for this approach:
1. I would want to differentiate between "variances from estimate" vis
a vis "planned buffer". An example might be in case of software coding
- The coding activity could be estimated for 40 hours and if the team
member takes 50 hours for this work item, then this should be tracked
as a variance against estimate. After coding would come testing. In
case of the testing producing any defects, then the team member would
have to spend effort on rework on the code piece. This work item of
rework is what i want to add as a buffer effort in the plan. I might or
might not use up this work effort, but this should be tracked
seperately from the extra hours used for coding.

The problem in this case would be that allocation of this effort, more
often than not cannot be planned as spending so 8 hours on this day -
this could be spread out across multiple days with the resource
spending some hours every day or something like that...

I hope my description was clear...

PS - LOOKS LIKE I HAVE SPAMMED MY OWN POST WITH THE INDIVIDUAL REPLIES.
I APOLOGIZE FOR THIS AS I WASNOT AWARE OF THIS. WOULD ENSURE ONE REPLY
TO ALL POSTS HENCEFORTH!!!!

 

[Mike Glen]

You're welcome, Jay

If you're getting into the percentages game, you might consider the crude
PERT offerings whithin Project, which, in effect, give you a bit of a buffer
for each task.


Mike Glen
MS Project MVP