how to interpret a pert chart
a pert chart is a visual representation of a series of events that must occur within the scope of a project s lifetime the direction of the arrows indicates the flow and sequence of events required dotted activity lines represent dummy activities these are items that are located on another pert path numbers and time allotments are assigned and shown inside each vector these charts have their distinct definitions and terms the most important of which is anticipating how long it will take to finalize a project a pert chart is similar to a critical path analysis which is another method that project managers use to chart tasks in a project the main difference between the two is that a pert chart uses various time frames and probability terms when estimating each project stage advantages and disadvantages of pert chartsas a project management tool pert charts have distinct advantages and disadvantages a pert chart allows a manager to evaluate the time and resources necessary to complete a project it also allows the manager to track required assets during any stage of production in the course of the project 3pert analysis incorporates data and information supplied by a number of departments this combining of information encourages department responsibility and identifies all responsible parties across the organization it also improves communication during the project and it allows an organization to commit to projects that are relevant to its strategic positioning 3pert charts are useful input for what if analyses understanding the possibilities concerning the flow of project resources and milestones allows management to achieve the most efficient and useful project path 3the information that goes into a pert chart can be highly subjective they may include unreliable data or unreasonable estimates for cost or time 3pert charts are deadline focused and might not fully communicate the financial positioning of a project creating a pert chart is labor intensive and maintaining and updating the information requires additional time and resources continual review of the information provided as well as the prospective positioning of the project is required for a pert chart to be of value 3managers can evaluate time and resources to complete projectassets required can be tracked during the course of projectincorporates data and information from all departmentsimproves communicationuseful input for what if analysesmay include unreliable data or unreasonable estimatesmay not fully communicate project s financial positioningneeds a lot of time labor and project positioningpert chart vs gantt chartthe gantt chart goes back even further than the pert chart american mechanical engineer henry gantt designed it sometime in the second decade of the 20th century and it remains the most widely used project management chart 4like the pert chart the gantt chart is a graphical depiction of a project timeline presented as a horizontal bar chart it records the start and completion dates of each element of a project and indicates their interdependencies the two charts are used in similar ways early versions of the gantt chart did not show dependencies that is it didn t indicate where a delay in the completion of one task could hold up the start of another task potentially throwing a whole project off schedule later versions of gantt corrected this although it may be difficult to interpret the pert chart is often preferred to the gantt chart a project management tool because it identifies task dependencies in some cases though project managers may use a pert chart as part of the planning stage of a project and a gantt chart to monitor its execution 5example of pert chartpert charts were first created by the u s navy s special projects office in the 1950s to guide the polaris fleet ballistic missile project using the pert model navy project managers were able to the success of this initial use of pert charts has caused them to be used ever since in many industries 