PERT and GANTT Chart in Changing the Car Tyre - Report Example

Critical path analysis, PERT, and GANTT chart in changing the car tyre Project managers use the critical path method (CPM) and its probabilistic version, the Project Evaluation and Review Technique or PERT, for systematizing project management (Banerjee and Anand 1997, p. 2). According to Banerjee and Anand, the use of the two tools makes possible cost planning and budget allocation. PERT originated from the 1950s (Stretton 2007, p. 1; Haughey 2010, p. 1-2). Koskela and Howell (2002) have argued that the underlying theory of management is obsolete but whether there is merit into their arguments or not, the PERT-CPM and the Gantt chart are continually being used in project management. The Project Model and its tools are still the model for software development in project management (Liang et al. 2000). An important tool used for the application of the PERT is a PERT chart. The PERT chart is figurative representation of the project implementation schedule, showing the task sequence and which of the tasks can be implemented simultaneously in order that work deadlines can be met (Concordia University 1999). The Concordia University (1999) material recommends the following steps for a PERT approach to project management: 1. Identify all the tasks of the project. 2. Identify the first task required for the project. 3. Simultaneously, identify also the tasks that be implemented simultaneous with the first task. 4. Identify the second task and identify the all the other tasks that can be done simultaneously with the second task and follow the pattern for the succeeding tasks. Other materials on the PERT-CPM, however, would argue that the above best describes the CPM component of the PERT-CPM rather than its PERT component. The application of PERT-CPM can be statistical as the version articulated by Bricker 1997 but it is also possible to devise and implement a PERT-CPM version that is relatively simple and not very statistical or even non-statistical. The PERT in PERT-CPM can be as pragmatic as a Project Evaluation and Review Technique or as sophisticated as a PROBABILISTIC Evaluation and Review Technique. Bricker (1997, p. 1) distinguished CPM from PERT in the description that the CPM assumes that the human activities can be determined with certainty while, in contrast, the PERT assumes that man’s activities and duration for the activities are random variables that are normally distributed. This means that the duration of man’s activities has a range, mean, and a probability distribution. Stretch 2001 has the same perspective (p. 1-2). Bricker’s articulation (1997, p. 2) of PERT, for instance, say that the PERT assumes the following: Duration of activity is a random variable and it has a BETA distribution and that The Central Limit Theory can be applied on duration of human activities. Obviously, articulating PERT in a statistical manner provides sophistication to the PERT-CPM. The sophistication may be however unnecessarily. It is possible that a statistical approach to the PERT-CPM will only provide a source of weakness when the PERT-CPM is used for relatively simple projects. However, it is possible to pragmatically overcome the weakness that can be associated with the CPM, PERT, or PERT-CPM by providing simple allowances and contingencies. For example, the duration allowance for each step of project implementation may have to factor in uncertainties or unanticipated factors that can delay project implementation. Instead of two days, for example, the time allocated for a certain activity can be stretched into three days or even four days instead to provide for the unforeseen or unanticipated. Of course, the allowances for delays and the unforeseen must be reasonable because speed of project implementation is also important. In contrast, the approach of Stretch 2001 in PERT-CPM is to use the mean figures for the duration of activities needed in project implementation. There can be project implementation activities from A to N while the duration of implementation can have a minimum of duration a and a prolonged implementation of duration b with a mean n as shown in Table 1. Table 1. Activities A to N implementation from duration a to b with mean duration m Source: Stretch 2001 p. 7 In the articulation of Stretch 2001 (p. 7), the a, b, and m refer to the following: The curve pertains to the distribution of the implementation durations based on prior experience. “Most likely” can refer to mean, median, or mode but Stretch (2001) had used the mean. Meanwhile, we can interpret the critical path in the PERT-CPM to mean the paths that can significantly reduce project implementation time at good quality. The CPM in the PERT-CPM can be interpreted to mean the paths that are decisive for a speedy project implementation with a good quality of work. Of course, we know that the CPM focuses on the critical path that is crucial for project implementation. It is possible to computerize the practice of the CPM and PERT (Critical Tools 2010, p. 4). However, project implementation that requires only a few sequences need not require a computer program. Further, in the opinion of the writer, a project manager can employ a pragmatic approach in the practice of PERT-CPM. For instance, even prior to the use of the PERT-CPM, a pragmatic question can be asked: what are the alternative routes or methods for implementing the project? What are the benefits and costs of the each option? Are there other options for implementing the project? What option is the best option given the benefits and costs and circumstance applicable to the project manager? For this writer the said questions are the initial questions that have to be addressed first prior to the application of the PERT-CPM. It is also possible to apply an initial PERT-CPM to each of the possible alternative ways of implementing the project. The route or alternative way of project implementation that possess the benefit-cost features and duration of implementation that suits the requirements of the project manager is then chosen. After these two steps, a detailed application of the PERT-CPM is then employed on the option chosen for project implementation. For example, in replacing a tyre, there are actually at least two options: hire somebody to do it or do the replacement yourself. One must first decide on these two options in project implementation before a PERT-CPM can be designed. Assuming one decided to replace the tyre by himself, a GANTT chart for the project can be something like Table 2. Table 2. Gantt chart for changing tyre ACTIVITY HOUR COST 1 2 3 4 Order and delivery of tyre x x £120 Prepare all tools needed x Remove old tyre x Attach new tyre x The PERT for replacing the tyre can be something like Table 3. Table 3. PERT for changing tyre Activity Predecessor Time in hours Expected Time Optimistic Normal Pessimistic Order and delivery of tyre 1 2 48 1 Prepare all tools needed 0.5 0.5 2 0.5 Remove old tyre 1 1 2 0.5 Attach new tyre Order and delivery of tyre and remove tyre 1 1 2 0.5 For the Gantt chart and PERT, we draw on the experience of Bucaro 2002, eHow 2010, and Merityre 2008. Comparing our Gantt chart and our PERT, we see that although we have allocated four hours to allow for contingencies and the unforeseen in the replacement of the old tyre, we expect the tyre change project to be finished within 2.5 hours. The critical path analysis or CPM for the project to replace the old tyre can be something like Figure 1 on the next page. In constructing our critical path analysis, We drew on Stelth and LeRoy (2009), Stretch (20001), Todman (2008), and the University of California (2010) for additional information on the techniques of replacing car tyres. The critical path analysis indicate that the order and delivery of the new tyre, the preparation of the tools needed to change the tire, and the removal of the old tyre will be the most crucial tasks prior to the actual replacement of the tyres. Figure 1. Critical path analysis In conclusion, large or small, sophisticated or simple, project management can use the tools of PERT-CPM and the Gantt chart. Bibliography Banerjee, A. and Anand, P. 2007. On path correlation and PERT bias. University of Florida: Department of Computer & Information Science and Engineering. Available from: http://www.cise.ufl.edu/~arunava/papers/ejor-spl-PERT.pdf [Accessed 24 June 2010]. Bricker, D., 1997. PERT: Project Evaluation and Review Technique. University of Iowa: Department of Industrial Engineering. Available from: http://www.icaen.uiowa.edu/~dbricker/Stacks_pdf2/PERT.pdf [Accessed 24 June 2010]. Bucaro, S., 2002. How to change a flat tyre. Consumer Information-UK. Available from: http://www.etyres.co.uk/consumer-information/change-flat-tyre.htm [Accessed 24 June 2010]. Concordia University, 1999. PERT Chart. Available from: http://web2.concordia.ca/Quality/tools/20pertchart.pdf [Accessed 24 June 2010]. Critical Tools, Inc., 2010. PERT Chart expert: Quick reference guide. Available from: http://www.criticaltools.com/FTP/PERTGuide.pdf [Accessed 24 June 2010]. eHow, 2010. How to replace a car’s tires. Available from: http://www.ehow.com/how_2089817_replace-cars-tires.html [Accessed 24 June 2010]. Haughey, D., 2010. A brief history of project management. Project Smart Company-UK. Available from: http://www.projectsmart.co.uk/brief-history-of-project-management.html [Accessed 24 June 2010]. Koskela, L. and Howell, G., 2002. The underlying theory of project management is obsolete. Proceedings of the PMI Research Conference, 293-302. Liang, B., Chen J., and Wang, F., 2000. A project model for software development. Journal of Information Science and Engineering, 16, 423-446. Merityre, 2008. How to change a car tyre. Merityre Company-UK. Available from: http://www.merityre.co.uk/blog/index.php/2008/11/26/how-to-change-a-car-tyre/ [Accessed 24 June 2010]. Stelth, P. and LeRoy, S., 2009. Project analysis through CPM (critical path method). School of Doctoral Studies Europe, 1 (July), 9-51. Stretch, C., 2001. CPM, PERT and EOQ. Available from: http://www.infc.ulst.ac.uk/~chris/or/pert.pdf [Accessed 24 June 2010]. Stretton, A., 2007. A short history of modern project management. PM World Today, 9 (4), 1-18. Todman, J., 2008. How change a car tyre. Available from: http://www.artipot.com/articles/247159/how-to-change-a-car-tyre.htm [Accessed 24 June 2010]. University of Southern California, 2010. Replacing tyres on your vehicle. Available from: http://www-scf.usc.edu/~bittman/tyres.html [Accessed 24 June 2010]. Read More