Which of the following is NOT one of the Seven QC Tools?

The reason that portfolio analysis is not considered one of the Seven Quality Control (QC) Tools is that the Seven QC Tools focus specifically on methods used to improve process quality and problem-solving in manufacturing and service sectors. These tools include flowcharts, histograms, Pareto diagrams, control charts, check sheets, cause-and-effect diagrams, and scatter diagrams.

Portfolio analysis, on the other hand, is more associated with strategic management and investment analysis rather than quality control processes. It involves the evaluation of various investment opportunities or business units to determine their potential return on investment, risk, and alignment with corporate strategies. Since it does not align with the primary purpose of the Seven QC Tools—enhancing quality and operational effectiveness—portfolio analysis is excluded from this set.

This understanding reinforces the importance of focusing on the specific attributes and applications of the Seven QC Tools, which are designed explicitly for identifying defects, analyzing causes, and facilitating improvement in operational performance.