Design Control Guidance - Food and Drug Administration

Tasks for all significant design activities, including verification and validation tasks, shouldbe included in the design and development plan. For example, if clinical trials areanticipated, there may be tasks associated with appropriate regulatory requirements.For complex projects, rough estimates may be provided initially, with the details left forthe responsible organizations to develop. As development proceeds, the plan shouldevolve to incorporate more and better information.The relationships between tasks should be presented in such a way that they are easilyunderstood. It should be clear which tasks depend on others, and which tasks need to beperformed concurrently. Planning should reflect the degree of perceived development risk;for example, tasks involving new technology or processes should be spelled out in greaterdetail, and perhaps be subjected to more reviews and checks, than tasks which areperceived as routine or straightforward.The design and development plan may include a schedule showing starting and completiondates for each major task, project milestone, or key decision points. The method chosenand the detail will vary depending on the complexity of the project and the level of riskassociated with the device. For small projects, the plan may consist of only a simple flowdiagram or computer spreadsheet. For larger projects, there are a number of projectmanagement tools that are used to develop plans. Three of the most commonly used arethe Program Evaluation and Review Technique (PERT), the Critical Path Method (CPM),and the Gantt chart. Software is available in many forms for these methods. Whenselecting these tools, be careful to choose one that best fits the needs of the project. Someof the software programs are far more complex than may be necessary.Unless a manufacturer has experience with the same type of device, the plan will initiallybe limited in scope and detail. As work proceeds, the plan is refined. Lack of experience inplanning often leads to optimistic schedules, but slippage may also occur for reasonsbeyond the control of planners, for example, personnel turnover, materiel shortage, orunexpected problems with a design element or process. Sometimes the schedule can becompressed by using additional resources, such as diverting staff or equipment fromanother project, hiring a contractor, or leasing equipment.It is important that the schedule be updated to reflect current knowledge. At all times, theplan should be specified at a level of detail enabling management to make informeddecisions, and provide confidence in meeting overall schedule and performance objectives.This is important because scheduling pressures have historically been a contributing factorin many design defects which caused injury. To the extent that good planning can preventschedule pressures, the potential for design errors is reduced.However, no amount of planning can eliminate all development risk. There is inherentconflict between the desire to maximize performance and the need to meet businessobjectives, including development deadlines. In some corporate cultures, impendingdeadlines create enormous pressure to cut corners. Planning helps to combat this dilemmaby ensuring management awareness of pressure points. With awareness, decisions areSection B Design and Development Planning 3/11/97 Page 11