Some Observations on Project Scheduling

Many progressive engineers have attempted to plan and schedule moderate construction projects mostly unsuccessfully. This is despite the most advanced academic theory, sophisticated computational equipments and rigorous automated procedures of modern times. Successful project management never emerges despite earnest efforts: is this due to differences between theory and practice, inefficiency of modern technology or mismanagement of scheduling engineers?

Whatever be the reasons, scheduling has remained a mystery that demoralizes engineering community. Engineers with unsuccessful experience in project planning have given up the idea of rigorous scheduling as unpractical and have adopted management by day-to-day control of activities without a pre-engineered baseline. If a schedule is not useful in practice, the effort used in preparing it is an unnecessary overhead – cost can be saved by not scheduling, rather. Many other engineers still prepare schedules, for documentation purposes alone with little managerial applications. Few construction managers make contractors prepare weekly or monthly schedules and track project progress based on the submitted schedules, without attempting to revise or refine the plan holistically. Control is applied on what is, but thought is not applied on what could have been. Many construction companies also feel that conventional and run-of-the-mill projects such as construction of apartments, does not derive any advantage by scheduling, even if scheduling as a method were successful.

However, it cannot escape our attention that most projects around us (including conventional and run-of-the-mill types) have not been completed on time. Given the competitive economy of the day, builders are required to give consumers more utility at lesser costs. The importance of cost reduction on intangible components such as time cannot be over-emphasized, but to date there is no effective mechanism to make at least 80% control on construction projects possible.

Certain observations can be made about current practices of scheduling

Rigorous Schedules

1. Engineers tend to plan and schedule the project at initial stages rigorously and submit baselines for on-site control. This requires larger initial effort and more important, rigorous schedules require equally rigorous implementation and monitoring leading to failure at implementation stages.


2. Rigorous schedules cannot necessarily accommodate potential contingencies and unforeseen problems. There is no simple technique such as allowing contingencies in project cost estimates when it comes to project scheduling.


3. In most cases, information required for rigorous schedule such as extent of working capital available, interest cost of borrowed capital and extent of availability of materials, equipments and labour on credit is uncertain. Managers with sufficiently long experience to quantify the above parameters are seldom well versed with technology of scheduling. The cost of collecting information on a most-probable-basis by surveys is usually very high.

Shortest-path Schedules and Working Capital Management

1. Planning engineers usually concentrate on minimizing the time period of construction while scheduling. However, shortest period of construction need not be necessarily be the objective of the company for most moderate constructions. Expedient construction is important for contracting organizations executing time-bound projects; for other companies faster construction may involve escalation of costs, in terms of working capital requirements. This makes shortest-time-schedules to fail due to apparent working capital mismanagement.


2. Working capital on projects may comprise of borrowed and relatively free funds, such as own investments, retained earnings, capital released by sale of previous projects or capital generated by sale of developments in advance of construction.


3. Consider a stage of project where company needs to borrow capital in order to operate the project on schedule. If the company expects realization of a free fund in few days, it may attempt to deliberately delay schedule rather than increase liability. Under these circumstances, it is necessary for scheduling engineer to evaluate the cost of delay of project at every stage of construction. If the cost of delay is greater than the cost of borrowed capital, the company needs to borrow and maintain the schedule whereas if it is not company should delay the project.


4. The cost of delay includes interest cost of already borrowed capital during the delay period, cost of hired equipments and daily labour in the middle of work, overhead cost such as site office rents and site engineer salary during the delay period, loss of credit advantage on already purchased materials and hidden cost due to staggering of turn-over. Unfortunately, most minimum-time-schedules evaluate projects for a given time-frame but do not analyze possible cost-overruns due to prescribed delays at every stage of construction. It is necessary to make the schedule an information system for managerial decision making rather than as a document of tracking a hard-and-fast criterion.
5. The objectives of scheduling may be different for different organizations. Scheduling objective may be to

• Reduce time period of construction irrespective of any actual or hidden cost escalation


• Minimization of actual cost which may or may not require reduction of duration of construction


• Minimization of hidden costs which may or may not require elongation of duration of construction

Managerial Coordination

1. Construction assignments are seldom undertaken single-handedly by one person or organization. There are a number of small players involved – architect, engineers, material suppliers, sub-contractors, labour contractors, casual labourers, equipment suppliers. It is important that information regarding the project schedule should reach each concerned organization or person by coordination.


2. If one of the organizations fails to make a commitment there is necessarily a schedule delay usually accompanied by a cost over-run. Procurement schedule of goods or services from different people is seldom created from a project schedule. Consequences of delay in procurement need to be highlighted and suitable alternate arrangements needs to be planned.


3. Sometimes schedules itself affect project organization. Consider for example a linear running meter process such as laying drainage channel. The process is characterized by a continuous fast process say excavation, followed continuous slow process say concreting the channel, then by a fast process say plastering of channel walls. Suppose there is also an imposed restriction that open excavation should be closed with cover slabs after a limited number of days. The direct approach of scheduling may be to consider the project as four continuous events: excavation starting from the first day, concreting starting from the second day, plastering starting after curing period say seven days followed by placement of cover slabs from tenth day. This schedule may not be successful because excavation and plastering being relatively faster jobs are out of phase with concreting. This may either result in idle labour/equipment for excavation and plastering or employment of plastering and excavation labour/equipment intermittently. Else it may be necessary to perform double work of placing the cover slab after excavation/concreting, removing them for concreting/plastering and replacing them again. The schedule needs to assist the project administrators in deciding which method of scheduling is best.


4. Schedules should also make parametric study on procurement of labour and equipments. For instance on a job of raising n number of RC columns what is the least cost schedule using m column boxes out of which k boxes are owned and (m-k) are hired? The schedule in this case should consider the number of days of job for different values of m, and calculate labour and other costs during that period to select that value of m that gives least cost. Academic routines are available today to treat such types of problems but these are not practiced and time tested.


5. Project plans should also assist the site engineers on day-to-day decision making for tracking purposes. For instance, consider a continuous concreting job with tight schedule of prescribed quantity of concrete per day. Suppose due to some unforeseen reason such as failure of equipment, only 75% of the prescribed quantity could be completed on a day. Is it advisable to carry over the remaining 25% to next days work or to complete the work on the same day by staying over-time? For this purpose, schedules need to specify the opportunity cost of cost components with respect to the work activity and project stages.


6. Many times top management of companies is not capable of appreciating schedule information in paper. Planning engineers may not possess vested powers for implementation of the schedule. Under such conditions, engineers may have to simulate different possible schedules in order to objectively make advantages of adhering to the schedule evident.

Some Guidelines

Based on the above observations, some guidelines can be arrived to make practicable work schedules.

Schedules should be on multiple tier architecture in following levels and characteristics.

1. Each activity such as concreting involving shuttering, bar-bending, placing of reinforcement, concreting and curing should be worked out for different parameters at one level to form a database of different work organization such as item rate, daily labour, lump sum, RMC, hired/owned equipments & labour contract for activities. Opportunity cost of parameters such as delay, credit, cost of capital etc need to be quantified for each activity. This database then becomes reusable again and again on projects.


2. The second level of schedule may consist of phases of the project such as foundation, floor concreting, painting etc. To begin with, the minimum time schedule may be applied on these project phases. The procurement and cash flow schedules may be derived from this shortest-time schedule. At this level on a generic day, various activities take place. Opportunity cost of parameters such as delay, credit, cost of capital, overhead expenses etc at every stage may be quantified by adding those for all activities at that stage.


3. The third level of schedule comprises of different project schedules incorporating parametric differences at second level. With broad outlines specified on this schedule it may be possible to exercise appropriate control over the schedules prepared by sub-contractors on periodic basis.

This multiple-tier scheduling may be academically similar to superimposition of optimization by dynamic programming with optimization by network programming.

The schedules prepared in the above format may be operated in the following manner

1. For every project only the third level project planning needs to be done because database of first level and arithmetic logic of second level scheduling may be available or may be developed based upon actual requirements. Thus, schedule becomes an information system for managerial decision making.


2. Let working schedules be prepared by subcontractors on periodic basis. The working schedules may be studied and modified against fair schedules that represent the requirement of the projects.


3. Monitor the schedules for project objectives and wherever there is a deviation, its impact needs to be quickly analyzed and corrective measures may be taken. If the deviations are due to unpredicted practical conditions the logic of schedule needs to be revised.


4. It may be better to employ singular person within the organization or external agency to be in charge of entire project, including interaction with auditors and financiers.


5. Unlike a building plan or structural detail, project schedule is not a document to be followed at a project. It is a language to interact. Schedules are similar to schemes prepared by architects. Schemes change many times during discussions between architects and clients; the changes diminish as design and construction are progressing. Schedules need to change during construction; all associated features need to be reanalyzed.

The aforesaid methodology is nevertheless, not ruthlessly practiced or time tested in the knowledge of the author. Suitable modifications or grossly different methodologies to confront the problems may also be possible. The objective of this document is to create awareness among construction companies that academic research on schedules is better sponsored and carried out by the industry with association from academia and software development companies