schedule variance

Reliability Planning

The key feature in the success of most new products is reliability, the capacity of the product to consistently perform according to requirements. Customer satisfaction is based on reliability, not just first-time performance. But reliability is a major cost factor in development, thus it is important to use the right tests for reliability and get them right the first time.

The reliability plan is the approach to defining acceptable reliability and testing the product in development. Reliability criteria are driven by customer requirements, another reason to make sure customer requirements are correct to begin with.

Reliability requirements can be very technical and quantitative, stating how the product will perform under specific conditions and stress. These requirements can also address field support standards, e.g., one service call per year. Sometimes technical standards such as "mean time between failures" can be used. Sometimes a reliability model is developed to simulate performance under various conditions. For instance, in the case of the plastic grocery bag, the extent of flexibility in the bag when loaded, e.g., how much it stretches, is stated in terms of maximum amount of stretch.

Setting reliability objectives

Setting reliability objectives is a tricky business, and the process has management and cost implications. Since customer requirements drive reliability standards, these requirements should be clear. However, for a brand new product it may be difficult to state those requirements without field testing. This is not a case of getting the best reliability you can get in development. This approach would be expensive and sometimes dysfunctional, and yet without careful

TABLE 5-5 Reliability Objectives and Requirements Template

Product or component

Conditions of use

Reliability objective (narrative)

Reliability targets (measure)


Vibration Water

Describe range for design

MTBF, number of failures in range, operating time

Customer is instructed to operate within specified temp ranges; product is designed to operate within those limits



Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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