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	Robust Control Chart	Kontrollkort – Statistisk processövervakning med Shewhart-diagram
Ämnesområde	Försöksplanering	Försöksplanering
Familj	Process / pipeline	Process / pipeline
Ursprungsår	1989–1997 (foundational period)	1924 (first use); 1931 (seminal book)
Upphovsperson	David M. Rocke; L. G. Tatum (key contributors)	Walter A. Shewhart (Bell Labs)
Typ	Statistical process monitoring technique	Statistical monitoring and control technique
Ursprungskälla	Tatum, L. G. (1997). Robust estimation of the process standard deviation for control charts. Technometrics, 39(2), 127–141.	Shewhart, W. A. (1931). Economic Control of Quality of Manufactured Product. Van Nostrand.
Alias	robust Shewhart chart, outlier-resistant control chart, robust SPC chart, distribution-free control chart	Shewhart chart, process-behavior chart, SPC chart, quality control chart
Närliggande	6	6
Sammanfattning	A robust control chart replaces the classical mean and standard deviation estimators in a Shewhart-style chart with resistant alternatives — such as the median and median absolute deviation (MAD) — so that a small fraction of outliers or non-normal process data cannot distort the control limits. The approach preserves the real-time monitoring logic of standard control charts while protecting against inflated or deflated limits caused by contaminated Phase I reference data.	A control chart is a time-series graph with statistically derived upper and lower control limits that separates the natural, random variation of a process (common cause) from unusual, assignable variation (special cause). Invented by Walter Shewhart at Bell Labs in 1924, control charts remain the foundational tool of Statistical Process Control and are used across manufacturing, healthcare, software, and service industries to monitor whether a process remains stable and predictable over time.