Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...

Control charts have two general uses in an improvement project. Undeniably, the most common application is as a tool to monitor process stability and control. A less common, although some might argue ...

A control chart plots measured values along with upper and lower quality control limits. Values appearing outside these limits are unacceptable and could indicate a manufacturing problem. Although ...

The extent to which products meet specifications needs to be systematically monitored in a production process. Product quality will typically be defined by two quantities: deviations from stated ...

Many types of control charts have an ability to detect process changes that can weaken over time depending on the past data observed. This is often referred to as the "inertia problem." We propose a ...

Journal of the Royal Statistical Society. Series C (Applied Statistics), Vol. 40, No. 1 (1991), pp. 1-12 (12 pages) A standard combined Shewhart-cumulative score quality control scheme for controlling ...