Project Planning Techniques
Managing projects to time and budget is important to project managers – their
reputations depend on it. It is important to clients of projects – they want to s ee res ults
either yes terday or today!
Us ing planning techniques can help project managers to work out what needs to be
done, in what order and when if they are to complete the project s atis factorily.
This article covers four planning tools :
tas kboarding
dependencies
network diagrams /critical path method
Gantt charts
An example runs through the article. It deals with planning a new training programme.
Taskboarding
Tas kboarding is us ed to identify what needs to be done in a project and in what order. It
is an eas y way of s orting out the blocks of work that mus t be done and which blocks
mus t be completed before others can s tart.
To tas kboard:
brains torm activities and jot them down on Pos t-It notes
rearrange the Pos t-It notes in order by as king: “What needs to be completed
before we can s tart?”
A tas kboard for a new training programme project is s hown below.
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Dependencies
This is the next s tep in planning – developing a dependencies table. This lis ts the tas ks ,
how long each will take and notes which need to be finis hed before others begin. The
s imple dependencies table can then be elaborated into the s tarting point for critical path
analys is .
The dependency table for the new training programme project is s hown belowf. Beware
of too many dependencies . Try to res trict what needs to be done before tas k X to the
abs olute es s entials , then other tas ks can be s lotted in around X.
Remember that if you have noted that B depends on A, and C depends on B, then you
do not need to note that C depends als o on A - that is automatically included in B.
For example, in the table below, G, Run the Pilot, cannot be done until the pilot is
des igned and marketed, and participants recruited, but it is s hown as dependent only
on F.
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Code Task
Depends Duration
on
(days)
A
Consult possible sponsors about
content of pilot.
B
Agree the objectives of the pilot
course.
A
10
C
Identify who will deliver the
course.
B
3
D
Design the content of the pilot
C
30
E
Market the pilot.
D
10
F
Recruit participants.
E
10
G
CONDUCT THE PILOT.
F
5
H
Evaluate the pilot results.
G
10
End
Decide the future of the
programme.
H
10
Developing a Network Diagram
A Network Diagram is a graphical way of s howing how the tas ks are interrelated – which
come firs t and which can be happening at the s ame time. By convention, all networks
begin with a ‘s tart’ box and finis h with an ‘end’ box. The network is drawn up us ing
information in the dependencies table.
The network diagram for the training programme example is s hown below.
To draw a network:
Draw a s tart box at the left of the page.
Show all activities that depend on nothing els e coming out of the s tart box.
Continue to add activities by drawing boxes to the right of the preceding tas ks .
Once all activities are s hown, draw them together to an end box.
Look out for activities that do not connect to any others or that do not connect to the
finis h box. Check the dependencies table - have you worked out logically what comes
before and after each tas k? Have you made all thes e connections on the network?
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Critical Path Analysis
Critical Path Analys is is us eful for es timating the total time that will be needed to
complete the tas ks and for identifying which tas ks mus t be completed on time if the
whole project is to s tay on s chedule.
The s tarting point for the analys is is the network diagram. This is then expanded to
include durations and s tart and finis h times for each activity.
The duration, how long a tas k will take in days , (or weeks on a large project), is taken
from the dependencies table. The labelling conventions and terminology are below.
EST
DUR
EFT
LST
LFT
Early Start Time. The earliest time that an activity can
start. This is the earliest that all the activities that
precede it can have been completed.
Duration. The time that the activity will take.
Early Finish Time. The earliest time that an activity can
finish. Calculated as the Early Start Time, plus
duration.
Late Start Time. The latest that an activity can start
and still be completed in time for the whole project to
remain on schedule. Calculated as Early Start Time,
plus float.
Late Finish Time. The latest time that an activity can
finish, without delaying the project as a whole.
Calculated as the Late Start Time, plus duration, or
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Early Start Time, plus duration plus float.
Float
The amount of time that an activity can slip and still
not delay the completion of the project as a whole.
In order to calculate thes e times , we take the following s teps :
Estimating early start and finish times
Move to the right over the network, filling in the early s tart times by as king: “How s oon
can this activity s tart?”. The early s tarting time, will be the early finis h time of the
predeces s or tas k if there is only one, or the lates t early finis h time of the predeces s or
tas ks if there is more than one.
For example, the early s tart time of C is Day 20, the earlies t pos s ible time that B, its
predeces s or will be completed. The earlies t s tart time of G, however, is Day 53; its
predeces s ors are D, which cannot finis h before Day 53 and F which could finis h at Day
40. So, where two or more tas ks mus t be completed before another can begin, the
early s tart time of the dependent tas k is the lates t of the early finis h times of the
predeces s ors .
This forward pas s over the network is completed when you reach the ‘finis h’ box,
whos e early s tart time and early finis h time are identical, s ince duration is zero. The
EST/EFT is the s oones t that the project can be completed. In this project, the earlies t
that the whole project can be completed is 68 days from the s tart.
Estimating latest start and finish times
To es timate the lates t s tart and finis h times , we do a backward pas s moving to the left
over the network. The ques tion we as k now is : ”How late can this activity finis h without
delaying the overall project s chedule?”.
We s tart by as s uming the lates t finis h time for the ‘finis h’ box is the s ame as the early
finis h time. Thes e are often predetermined anyway - the finis h could be a s pecific event,
to which all other tas ks lead.
The lates t an activity can finis h, or lates t finis h time, is the lates t s tart time of the
tas k(s ) which come after it. For thos e which connect to the end box, the lates t finis h
time is the s ame as the end box’s time. For thos e tas ks which have two or more
activities depending on their completion, the lates t finis h time is the s oones t of the
lates t s tart times of its dependent activities .
We s ee that F, recruiting participants , could be complete by Day 40. But the cours e
cannot run until it is des igned (D – earlies t finis h Day 53), s o F need not be completed
until Day 53. Similarly, F need not s tart, therefore, until Day 43, giving a ‘float’ of 10
days . E (market the pilot) could be finis hed at Day 30, but could be finis hed as late as
Day 43 to allow F to proceed, giving a float of 13 days .
Calculating float
Float is the leeway or s lack of an activity. It is the amount of time that the activity can
s lip, without delaying the project completion. Float is calculated as the difference
between the earlies t a tas k can s tart (EST) and the lates t time it can s tart (LST).
Identifying the critical path
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The critical path is the s equence of activities linking from s tart to end boxes which have
zero float. Thes e activities have no leeway to s lip. They mus t be s tarted and finis hed
on time if the overall project is to be complete at the planned date. The critical path for
the example is A, B, C, D, G, H as s hown below. Note that all tas ks are not on the
critical path: ‘critical path’ is , therefore, not s imply the lis t of tas ks that must be
completed. Critical path is the lis t of tas ks which mus t be completed exactly on
s chedule.
Drawing a Gantt chart
A Gantt chart is one of the mos t commonly us ed project planning tools . It is particularly
us eful becaus e it provides an eas y-to-unders tand vis ual dis play of project activities . An
example for the pilot programme project is s hown below. The s olid bars go from early
s tart date to early finis h date and the s tyle lines ( s ee below) repres ent float.
Style line example
Symbols to repres ent events , miles tones , work completed and s o on can be added to
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s how the s tatus of the activities , if des ired.
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