Modern twenty-four hours undertaking direction and particularly project programming goes back to the development of PERT ( Program Evaluation and Review Technique ) and CPM ( Critical Path Method ) . All of this was during the late fiftiess, which besides saw the creative activity of the Project Management Institute in 1969 ( Herber & A ; Deckro, 2010 ) . The PERT and CPM techniques of undertaking planning were developed rather independently. Originally both the techniques were based on sequencing Activities-on-Arrows ( AoA ) , a web diagram method. Another web method is Activity-on-Node ( AoN ) , which subsequently was called PDM, was initiated on 1 July 1958 by John W. Fondahl from the Civil Engineering Department of Stanford ( Stretton, 2007 ) . Latter technique is today the most used web sequencing method.
This paper aims to depict the procedure of sequencing and its inputs, end products, tools and techniques. Sequencing is a constituent of clip direction and eventually it contributes basically to the undertaking agenda, which has a critical impact on the overall undertaking work.
Problem country / Extent
In common sense, whenever the undertaking range is determined, and all needed activities are included in the WBS, it is highly of import to negociate within the undertaking squad the appropriate order of actions needed to be undertaken. The best manner to make this is to execute activity sequencing. Otherwise, all farther undertaking work will be influenced negatively due to possible misinterpretations or dissensions within the squad every bit good as unexpected holds, convergences or clangs.
This paper aims at look intoing the procedure of sequencing activities and ways to execute it decently. The job to be solved is to come up with the most appropriate tools and techniques, which guarantee logical and sensible order of all scheduled activities in the undertaking. For a clearer apprehension of the job it can be broken down into the undermentioned sub-goals:
To depict indispensable inputs for sequencing
To make up one’s mind upon methods to be used while working on the topic
To construct a theoretical model for the studied construct
To supply empirical grounds on the construct by utilizing the methods in a existent undertaking
To associate empirical and theoretical findings
To come up with general consequences and decisions about the topic
To demo the impact of sequencing for the whole undertaking success
Fulfillment of all these sub-goals will take to work outing the chief job of the survey. This will ensue in the development of an algorithm of actions that will assist to make up one’s mind on the proper activity sequencing.
The mentioned intent and sub-goals frame the extent to which the activity sequencing will be investigated.
This subdivision is aimed at uncovering the methods used for aggregation and processing information necessary to obtain desirable consequences. Methods by definition refer to the systematic, focussed and orderly aggregation of informations for the intent of obtaining information from them, in order to work out or reply a peculiar research job or inquiry ( Ghauri & A ; Gronhaug, 2005 ) . The chief grounds why methods should be identified and clarified before get downing informations aggregation is that they explain the logic of the survey and supply regulations for communicating during the work on the undertaking.
By and large, all methods used by the group in order to execute this survey can be divided into the undermentioned five groups:
Methods used to make up one’s mind upon the topic of probe
Methods used to construct theoretical model of the survey
Methods used to roll up and analyse empirical informations
Use of instance survey as an illustration
Discussions and written descriptions
Activity sequencing by agencies of MS Project
Methods to command work procedures
Scheduling: mileposts, meetings, single and group work
Methods used to guarantee quality in footings of dependability and cogency
Use of lone relevant and dependable literature beginnings and methods of informations aggregation and processing
Supplying description and reading for informations collected
Use of illustrations which are generalizable
Avoidance of participant mistakes: group determination devising, preliminary group treatments before put to deathing single undertakings, dual cheque of single work by all members of the group
By utilizing these methods we guarantee to carry through all the marks that were defined and the intent / job of the study will be solved.
Theories and theoretical accounts
All of the presented theories and theoretical accounts in this chapter are related to sequencing issues: inputs for sequencing, tools and techniques, end products. Furthermore, act uponing factors must be considered before sequencing activities is started in order to execute all undertaking phases successfully. The tradeoff between these factors will act upon the sequence of activities that have to be performed. This tradeoff is described below every bit good as other elements of activity sequencing procedure.
In today ‘s competitory environment the ternary restraint ” , including clip, cost ( budget ) and range, play an of import function when it comes to proper undertaking direction. Balancing these three restraints affects ever quality ( PMI, 2004 ) , a 4th restraint. If one of these parametric quantities is changed at least one other parametric quantity is affected ( PMI, 2004 ) . As a 5th restraint undertaking direction has to cover with the hazard. PMBOK ( PMI, 2008 ) includes the variable resources so in entire there are 6 restraints.
Figure 1: Constraints – Including the ternary restraints: Time, cost and range
The undertaking director has the duty to pull off and command these viing factors while taking attention of the stakeholders ( patrons, organisation ) chances. A clear prioritisation tradeoff of these restraints at the beginning of a undertaking is indispensable. Pull offing that tradeoff during the whole undertakings is a really of import portion and requires accomplishments and cognition of pull offing a undertaking. ( Wideman, 2010 )
PMBOK describes that undertaking direction has to equilibrate these restraints in order to do a undertaking successful ( PMI, 1996 ) .
In decision, the right combination of these restraints determines the efficiency and effectivity of a undertaking. In order to sequence undertaking activities these factors play an of import function.
Definition of sequencing
Definitions refering the country of activities and their sequencing will be clarified in the followers.
Activity is a constituent of work ( with defined length, cost, and resources that should be performed ) during a clip of the undertaking ( PMI, 2004 ) .
Activity Definition Process is a procedure to place the deliverables of the lowest degree ( work bundles / activities ) of the Work Breakdown Structure ( WBS ) ( PMI, 2004 ) . It is the foundation for the more elaborate activity list.
Activity Sequencing involves placing and documenting the logical relationships ( dependences ) among agenda activities ( PMI, 2004 ) . The rule of sequenced activities is that each activity has, harmonizing to Taylor ( 2008 ) , another activity before it ( predecessors ) or after it ( replacements ) . In order to execute sequencing, different tools like manual 1s, automatically 1s or both of them in combination can be used ( PMBOK ) . Furthermore, by sequencing activities of a undertaking some of the most powerful undertaking agenda tools, such as web diagrams and critical way analysis can be used. ( Schwalbe, 2010 )
Input for activity sequencing
As was shown supra, activity sequencing is a portion of the undertaking clip direction procedure aimed at agenda development. Merely scheduled activities are to be used for sequencing during which the logical relationships between them should be identified and documented. Activity sequencing normally takes topographic point after the definition of activities and uses its end products. Therefore, it would be utile to depict cardinal end products from the activity definition stage, which are as follows ( PMI, 2004 ) :
Approved alteration petitions
Another of import input for the sequencing of activities stage is a undertaking range statement. This will be used during the whole undertaking life rhythm and is non an end product of the activity definition stage. In footings of activity sequencing, the undertaking range statement provides premises and restraints on undertaking activities. These should be taken into consideration while developing the dimensions of activities and the relationships between them.
The activity list is to a big extent an end product of the WBS that includes all activities ( undertakings ) to be performed during the undertaking, which have been determined by the range of the undertaking. Therefore, all the activities included in WBS must be interpreted in footings of scheduled activities and used while fixing the overall activity list. Harmonizing to PMBOK, the activity list includes all scheduled activities that are planned to happen on the undertaking ( PMI, 2004 ) . Therefore, the activity list includes all activities and merely those activities which are required as a portion of the undertaking range. In this sense, the undertaking range statement is a mention point and one of the key inputs for activity sequencing.
The activity properties are given in add-on to the range description of activities presented in the activity list ( Sanghera, 2006 ) . They identify the multiple attributes associated with each agenda activity and include the activity identifier, activity codifications, activity description, predecessor activities, replacement activities, logical relationships, leads and slowdowns, resource demands, imposed day of the months, restraints, and premises ( PMI, 2004 ) .
The milepost list identifies all scheduled mileposts and indicates whether the milepost is compulsory ( required by the contract ) or optional ( based upon undertaking demands or historical information ) . The milepost list is besides included as a undertaking direction program constituent ( PMI, 2004 ) . Requested alterations are besides inputs for activity sequencing if they were generated and approved as end products of activity definition procedure.
All inputs contribute to the development of activity sequencing. The basic tools for sequencing are web diagrams which are explained in the undermentioned chapter.
Network diagrams are the basic end product of the activity sequencing ( PMI, 2004 ) which presents the activities and their dependences. Besides other inputs, sequencing is the foundation for the agenda development of each undertaking. Proper developed web diagrams help to develop accurate and realistic undertaking agendas and do a undertaking successful.
Undertaking agenda web diagrams visually present the sequence of undertaking activities and the relationship or dependences between them ( PMI, 2004 ) . Either they are produced manually are based on a package ( e.g. MS-Project ) .
Taylor ( 2008 ) describes general tips and facts for web diagrams as:
There is a starting and stoping point for each web
There are predecessors and replacements for all undertakings
There are no cringles
The web must be updated and current
Advantages: It shows the undertaking mutualities, every bit good as demoing the start and terminal clip and the critical way.
Disadvantages: It is non easy apprehensible, hard to update and is a sub criterion communicating tool.
Having detailed the pros and cons it is still an first-class planning, hazard appraisal, tracking and direction tool.
To properly sequence the defined activities there are several tools and techniques available. The two authoritative web diagrams are described in the undermentioned portion ( PMI, 2004 ) :
1 ) Precedence Diagraming Method
Precedence Diagraming Method ( PDM ) or activity-on-node ( AON ) is a web ploting method utilizing boxes or rectangles. It connects these boxes with pointers to show their dependences. Undertaking activities, defined in the first measure, and their relationships are plotted in a clear graph. The dependences can be divided in four types ( PMI, 2004 ) :
coating to get down – replacement starts with completion of predecessor
start to get down – replacement start with predecessor
start to complete – replacement completes with start of predecessor
coating to complete – replacement completes with completion of predecessor
Figure 2: Precedence Diagram Method ( Source: PMI, 2004 )
The advantages of this diagram type harmonizing to Taylor ( 2008 ) are: no silent person activities, inside informations all relationships and it is supported by most modern computing machine package.
2 ) Arrow Diagramming Method
Arrow Diagramming Method ( ADM ) is a web ploting method. In contrast to the PDM, the activities are shown as pointers and the dependences at the nodes. Therefore it is called activity-on-arrow ( AOA ) . ADM can merely show finish-to-start relationships. In some instances dummy ” activities are required which are illustrated as dash lines. Their continuance is zero. Maylor ( 2005 ) states that silent person activities are used when the logic of the activity sequence demands to be preserved or the diagram has to be clarified. For case, when two activities have the same start and terminal events.
Figure 3: Arrow Diagraming Method ( Source: PMI, 2004 )
The disadvantages harmonizing to Taylor ( 2008 ) can include ; it merely shows coating to get down relationships, no lead or slowdown can be applied, there is no possibility to add or deduct clip and there are dummy undertakings without continuance.
Schedule web templets
Schedule web templets are standardized templets for agenda web ploting. Their application is sensible when undertakings have similar or about indistinguishable deliverables and therefore indistinguishable activities. These templets can frequently cover subprojects but seldom whole undertakings. In this paper no farther attempt is made on the engineering.
To find sequences of the activities there are three types of dependences ( PMI, 2004 ) :
Mandatary: They are built-in in the nature of work being done and frequently affect physical restrictions, e.g. construct something before it can be tested
Discretionary: They are non based on rigorous logic, but instead on pick. Several sequences or connexions are possible. Knowledge and experiments of former successful undertakings influence the determination.
External: they involve a relationship between undertaking activities and non-project activities. E.g. a provider must present a portion before trail tally starts
Using leads and slowdowns
To depict all dependences or logical relationships accurately, leads and slowdowns need to be added.
Lead: allows acceleration of the replacement activity or overlapping with the predecessor
Slowdown: directs a hold in the replacement activity
By using the methods above the sequencing procedure is about finished and the agenda can be developed. To better the agenda farther the methods described in the following portion can be applied.
Accelerating a undertaking
Accelerating a undertaking is a major and really of import portion when it comes to be aftering a undertaking. In most undertakings clip is a important resource that should be considered really carefully.
After the process of making a agenda ( web, Gantt etc. ) is done the following logical measure is to better the agenda. Bettering the agenda means executing alterations in order to speed up the undertaking. It should be noted that this might ensue in altering the sequence of activities. This can be done, depending on the ground, before or during the executing stage of the undertaking. Some grounds why a undertaking should be accelerated are listed in the followers ( Mubarak, 2010 ) :
normal ” finish day of the month in the planned agenda does non run into the imposed finish day of the month of the contract
during the executings stage of the undertaking one realizes that the undertaking is behind agenda
one wants to complete before agenda in order to get down another undertaking earlier and therefore doing more net income ( e.g. building industry )
In order to speed up a undertaking several methods can be applied. In the undermentioned different methods are mentioned ( Mubarak, 2010 ; Taylor, 2008 ) . The focal point lies on methods that are connected to sequencing activities or to the major technique of scheduling betterment, which might act upon the sequence:
Revisit or analyze the agenda
Revisit or analyze the agenda exhaustively to happen any mistakes or unneeded logic or restraints. Using the finish-to-start ( FS ) relationship when a start-to-start ( SS ) relationship with sensible slowdown can work is the most common booby trap. This method merely aims to better the agenda by taking the right logics and restraints. The hazard of the undertaking will non be increased by this method ( Taylor, 2003 ) .
Figure 4: Accelerating a undertaking by replacing FS relationship by a logical lead
Fast-tracking is a technique in order to speed up a undertaking by agencies of get downing an activity ( or a whole stage ) before the precursory activity ( stage ) is non finished yet. Concurrent ( Simultaneous Engineering ) are widely used methods utilizing the technique of fast-tracking. The difference between the technique, revisit or survey ” mentioned above every bit good as the technique of utilizing logical leads is, that fast-tracking will increase the hazard.
The process here is to look into all undertakings in order to find if any sequenced activities can be done in analogue. An illustration therefore is to get down with the building stage before the design is finished. In a traditional position the logical sequence is that the design has to be finished before building can get down. If you want to fast-track this illustration you start building of what you have a general, but non an exact, thought. The effect of this is that alterations in the design will do the work completed therefore far in building, unserviceable.
Figure 5: Fast-tracking of activities or stages
In order to use fast-tracking, leads must be created that are non based on a logical dependence and hence will necessarily increase the hazards. ( Taylor, 2003 )
Crashing the agenda
Crashing the agenda ( project / agenda crashing ) is a technique that aims to shorten the clip of activities of the critical way. In order to execute this technique decently the following cardinal points should be considered:
Merely activities in the critical way should be shortened because cut downing the continuance of undertakings which already have slack will non assist to short the overall agenda
To cut down the continuance of an activity normally means that extra resources are needed. This will increase costs and hence at that place has to be a balance between the factors clip and cost
Taylor ( 2008 ) further provinces that a combination ( where possible ) of agenda crashing and fast-tracking is normally the best option in order to better the agenda. But it is of import to maintain in head that fast-tracking the agenda increases the hazard and crashing the agenda adds costs.
Another facet sing the betterment of the agenda and which is connected to happening the right sequence is that the needful resources at a certain clip are non available. Talyor ( 2008 ) therefore explains the method of levelling resources. This technique is one major benefit of web analysis but seldom used.
The technique of levelling resources uses the float or slack within a undertaking in order to cut down the figure of resources needed at a certain clip. This technique is thereby limited to the bing slack and therefore can non ever be applied.
Figure 6: Levelling resources ( Beginning: Taylor, 2008 )
The procedure of levelling resources is like a mystifier where you have to play around ” in order to happen the optimum sequence of activities. One has to utilize the slack of the activities in order to travel them along the timeline in order adjust the degree of resources. For a more elaborate account see Taylor ( 2008 ) .
In this chapter the tools and techniques explained in chapter, are applied and described by presenting a practical illustration. Sequencing is concerned with seting the defined activities in the proper order. The authoritative tool is the web diagram AoN. The undermentioned illustration illustrates the chief stairss and advantages of the web diagram technique, including the finding of dependences, using leads and slowdowns, every bit good as undertaking acceleration
The undertaking is to sequence the activities in order to construct a ready-made-house. The undermentioned activities and mileposts are the input for the edifice undertaking.
Water recess and drainage
Milestone: cellar is finished
Delivery and arrangement of the house
Milestone: house edifice is finished
The activity list presented above was developed on the base of range statement and WBS. Correctly turn toing range direction allows the undertaking to run swimmingly, avoiding bumps along the manner and finally taking to a successful undertaking. The range in bend will supply a solid footing for the WBS.
A clear WBS is the foundation for developing a realistic activity list. Failure to sketch the WBS in a legible mode will ensue in hapless undertaking be aftering which in bend will ensue in activities being left out. Activities may hold been entered but with an wrong WBS they will concentrate on the incorrect countries.
Sequencing includes two chief techniques in an AoN they are, dependency finding and using leads and slowdowns. These tools are non on off events. During the full clip direction procedure these activities will hold to be adjusted and edited. Once the agenda development phase has been reached all clip direction processes must be complete. After this sequencing has a feedback cringle of information that will supervise the activities and command the existent clip sequencing.
Determine dependence type
To specify the sequence in the AoN the dependences and relationships of these activities need to be determined. In chapter 1.4 three chief dependences are introduced: mandatary, discretional, external.
Determining dependences allows the undertaking squad to analyze the right activity sequence. They do this to determine which activities can non happen before another and as such must be stalled or held back until the completion of the old activity. Determining this is highly of import because it will act upon the estimating of clip spans for activities, the logistical demands of resources and the allotment of man-hours. The fact that there are three sorts of dependences makes it hard to analyze them.
The following graph presents the different dependences for the house edifice activities.
Figure 7: Dependences
Compulsory dependences are logical decisions e.g. the house can be placed on the cellar when the expected harden ( foundation ) clip is finished. Parallelisation or overlapping these activities is physically non possible.
The bringing of the ready-made house is an external dependence. It is non a undertaking activity, but of import measure for the sequencing. Placement ca n’t take topographic point before the house is delivered. The bringing day of the month should be portion of the provider contract.
Discretionary dependences are logical decisions. There are several possibilities to set the activities in an order. Get downing one activity after the other is finished increases the continuance of the undertaking. Making activities parallel can or can non increase the hazard, but helps to safe valuable clip. Discretionary dependences influence the restraints, which are described in chapter 1.1, and hence the success of a undertaking.
Apply slowdowns and leads
Lags and leads, which are explained in chapter 1.4 can be applied in the following measure to depict the dependences accurately.
Adding a lead means to speed up the replacement activity. This allows the subsequent activities to happen Oklahoman. Hence, on a compulsory dependence a lead should non be applied. Within the house illustration this can be explained easy. Overlaping of the activities indurating ” and arrangement of the house ” is physically non recommendable. Adding a slowdown, to guarantee the hardening clip, would be the appropriate attack in this instance. Laging a dependence means leting for a clip buffer for the activity. This increases the length of clip allowed for an activity and as such lowers the hazard of the activity taking longer than expected.
In discretional dependences either slowdowns or leads can be added. The undermentioned illustration illustrates the practical usage of a lead in an activity sequence. After the house is placed, the activities interior ” and electricity ” can get down at the same clip. They do n’t act upon each other, do non do a higher hazard and enable a clip decrease.
Apply fast-tracking and crashing
Fast-tracking and crashing are utile techniques, which are applied during the agenda development of a undertaking to better the agenda. Both lead to a lessening in continuance but include a hazard, cost or resource addition, or a quality or public presentation lessening. The techniques and their influence are described in chapter 1.5.
For the house edifice examples fast-tracking would intend e.g. an imbrication of the picture ” and floor ” activities and hence accepting the hazard that the floor is smutted or damaged in order to safe clip. Get downing the rug ” besides before completing the floor in add-on would take to a continuance decrease about 3 yearss. Crashing the critical way activities could be applied for the interior ” portion. By increasing the figure of workers the continuance can be reduced from 8 to 6 yearss. Combination these techniques in the house illustration leads to a entire clip decrease of 5 yearss compared to the appraisal reach through using leads and legs.
The MS-project programs B and C, attached in the appendix, show the consequence of these two methods for the house constructing illustration diagrammatically.
The last chapter represented appropriate activity sequencing on the house building illustration. It showed clearly how to utilize the tools and techniques, when to utilize or non utilize them, in which order they should be used every bit good as the advantages and disadvantages. In this portion all of the of import issues for proper sequencing are summarized, evaluated and discussed.
While working on the study we figured out that some methods are easy to use and manage whereas others are slippery and need careful consideration to be employed likely. We will open the treatment with methods that are simple to use and so travel on with the more hard methods and discourse the debatable countries.
When working on the study the first of import measure was to specify the right input for proper sequencing. Having a deeper expression into the different inputs, defined in PMBOK, we decided that the most of import inputs in order to guarantee proper sequencing are the range statement, the WBS and the activity list. This portion did non raise any jobs.
In the following portion the most of import issues related to development of web diagrams were defined and evaluated. Different beginnings stated the AoN is the most practical and effectual technique to guarantee proper sequencing. Determination of the dependences while developing the webs was besides a chiseled and noncritical undertaking. Mandatory and external dependences can be defined easy, whereas the discretional type is trickier to manage every bit good as the following measure: applying leads and slowdowns.
The undermentioned portion includes the methods that are more complicated and hard to use. Discretionary dependences allow for several different waies of action to take from. Each of these has a different result and it will be up to the undertaking director to make up one’s mind which way is the best. When seting leads and lags one must be careful when altering activities that are linked to the concluding clip span, which is the critical way of the undertaking. Applying leads and slowdowns may act upon the continuance of the undertaking but does non take to a higher hazard or cost addition.
Most hard portion in this study was to separate between using leads and slowdowns and fast trailing, because both cause analogue or overlapping sequencing. After some research of different beginnings we could specify that the chief difference is in the increased ” hazard, which is included merely in fast trailing. Another tool for diminishing undertaking continuance is crashing, but can be easy applied if one is familiar to the effects, the addition of costs.
The work on the existent illustration house edifice ” showed us that even easy tools can acquire complicated in their usage when uniting them. It is non possible to give a general description of how to sequence activities or how to better the agenda. This has to be considered on a individual footing for each undertaking and each undertaking ‘s range and undertaking direction. We learned that a healthy ” mixture of these tools and techniques has to be defined for every unique undertaking.
In the edifice a house illustration it would non be appropriate to take utmost hazards ( fast-tracking ) in order to run into the day of the month, nor to raise the costs by taking extra resources ( crashing ) . The ideal procedure in this state of affairs would be to use both methods in order to derive the expected consequence. This would intend increasing the hazards and costs but merely reasonably. In this instance utilizing both methods up to a certain degree will likely take to the best consequence.
The theoretical model that was worked out ( see chapter ) and the empirical illustration constructing a house ” ( see chapter ) are taking to the undermentioned decisions.
The theoretical research showed that there are different solutions available to project directors to guarantee undertaking appropriate sequencing. Different beginnings province the same attacks and reference the same techniques and theoretical accounts. By using the theoretical theoretical account to the practical illustration it becomes clear that these theoretical accounts can be easy used and lead to suited sequencing.
The mentioned attack leads to an algorithm which was stated in chapter as the intent of this study. This algorithm should be carried out during sequencing activities and includes the undermentioned stairss:
Develop Network Diagram
Determine / Identify dependences
Apply leads and slowdowns
Use Network Diagram as input for scheduling
Better the agenda
By following these stairss one can maintain the tradeoff between the 6 act uponing factors such as cost, clip, quality, resources and hazard at acceptable degrees. Proper sequencing harmonizing to the developed algorithm will equilibrate the tradeoff and contribute to the overall success and public presentation of the undertaking.
The proper sequencing of activities can act upon a undertaking to such an extent that the misdirection of activity sequencing can take to monolithic undertaking failures. On the other manus though, the right use of activity sequencing can ensue in a undertaking that comes in under budget and early.
The algorithm for sequencing developed above should be applied carefully. When using the algorithm the undermentioned factors that should be taken in consideration:
Ensure that inputs such as WBS and activity list are complete and up to day of the month
Determine the dependences carefully ( immense influence )
Replace finish-start dealingss with start-start dealingss combined with a slowdown
Apply leads and lags where possible and necessary
Do n’t use leads an compulsory dependences
Look where work can be done in analogue
To speed up the full undertaking continuance use fast trailing, crashing, but be cognizant of the influence on the other undertaking restraints ( e.g. cost, hazard, quality )
Combine leads and slowdowns, fast-tracking, crashing to increase efficiency
Control logic of sequence precisely and on a regular basis during the whole undertaking
Focus on the whole undertaking when make up one’s minding what methods are executed and equilibrate the restraints to do undertaking successful
Appendix A – Activities sequenced in a row
Appendix B – Activities sequenced harmonizing dependences
Appendix C – Activities sequenced harmonizing dependences and fast-tracking + crashing
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