But Gantt charts are not perfect and all too often they become overly complex with too many dependencies and activities. This is a trap many new project managers fall into when they start using planning tools. It is much better to produce a clear and simple plan that shows the main work packages in summary, than a plan with so much detail the overall impression of project progress is lost. Let the work package manager put together the day-to-day detail of the activities within a work package, while the project schedule concentrates on the interfaces between project teams.
不過，甘特圖並不是完美的，由於有太多的項目依賴和活動，往往會過於複雜，這是許多新的項目經理在開始使用項目規劃工具時會陷入的陷阱。最好是拿出一個清晰而簡單的計劃來展示匯總的主要工作細目，而不是拿出涵蓋太多細節的計劃（如果這樣做，會讓整體項目進度丟失）。要讓工作細目的管理者把某個工作細目中的日常活動細節放在一塊，而項目進度則集中在項目團隊之間的接口上。
Neither are they good at showing the relative priorities of individual tasks and the resources expended on a task. Tasks are prioritised on the amount of float not their importance to the project. For example, they can clearly show the elapsed time of a task but cannot so easily communicate how many people may be needed to complete that task. So if not backed up by other data they can give a misleading impression to stakeholders. This is where using additional techniques such as a precedence diagram (sometimes called a PERT chart), for instance, becomes useful.
甘特圖，也太好顯示單個任務的相對優先級，以及在某個任務上所花費的資源。任務優先於提出量，而不是對項目的重要性。例如，甘特圖可以清楚地顯示出某個任務所用的時間，但卻無法輕易地告知需要多少人才能完成該項任務。因此，如果沒有其他數據來支撐，甘特圖則會給相關方帶來誤解。這就是使用其他的方法，例如優先圖（有時稱為PERT圖），變得很有用之處。
A precedence diagram is another powerful project management technique which is particularly useful for identifying complex inter-dependencies and showing relative priorities of activities and, hence, highlighting the tasks most critical to project success.
優先圖，是另一個強大的項目管理方法，尤其適用於識別複雜的相互依賴關係，並顯示活動的相對優先級，因此，要重點突出對項目成功最重要的任務。