QC7つ道具、新QC7つ道具（QC seven tools_ New seven tools for QC）
（１） QC7つ道具； QC seven tools
/ パレート図； Pareto diagram
/ 特性要因図； cause and effect diagram, characteristic diagram, Ishikawa diagram
/ チェックシート； check sheet
/ ヒストグラム； histogram
/ 散布図； scatter diagram, scattergram
/ 管理図（グラフ）； control chart, (graph)
/ 層別； stratification
（２） 新QC7つ道具； New seven tools for TQC
/ 親和図法； affinity diagram
/ 連関図法； relations diagram
/ 系統図法； tree diagram
/ マトリックス図法； matrix diagram
/ アローダイヤグラム法； arrow diagram
/ PDPC法； process decision program chart
/ マトリックスデータ解析法； matrix data analysis
/ The objective of stratification is to grasp a problem or to analyze its causes by looking at possible and understandable factors or items.
/ A Pareto diagram shows which defective items should be tackled first.
/ Checksheets come in several types, depending on the objective for collecting the data.
/ A scatter diagram is a tool for analyzing relationships between two variables.
/ A Histogram is a picture of variation or distribution, where data has been grouped into cells and their frequency represented as bars.
/ Control charts, first proposed by W. A. Shewhart of Bell Telephone Laboratories in 1924, are used for maintaining both process and manufacturing control in a stable condition.
/ Ishikawa diagram composed of lines and symbols is designed to represent the relationship between effects and their causes.
/ In its original form, matrix data analysis was heavy on mathematics.
/ The arrow diagram can be simple and straightforward, but over time its use has evolved to that of organizing and monitoring complex projects and situations.
/ Matrix diagrams can be used to show the relationship between two, three or four groups of information.
/ PDPC is a visual tool that combines and builds on elements of several other techniques.