PMBOK mentions 7 basic quality assessment tools that can be useful in determining and representing the quality of a process, a product or a service. These 7 quality tools are described below:
Cause-and-effect diagram (also called Fishbone Diagram, Ishikawa Diagram): Lets you find out the main causes of an effect and also helps you reach to the root cause of the problem.
Check sheet: A structured form used to collect and analyze information. It also acts as a check-list that you can use to ensure that all the required activities have been performed.
Control chart: This is a graph that shows how a process is performing over a time. It also lets you see whether the result of the process is under limits given by the customer and manager or not.
Histogram: It is a type of a graph that shows results in form of bars.
Pareto chart: It is same as Histogram except that the results are sorted in descending order
Scatter diagram: It shows the effect of changing one variable on another variable.
Flowchart: It is a graphical representation showing each or main steps of a process