There are quite a few quality management tools used in Six Sigma. You will find that most of them are more applicable only for certain DMAIC or DMADV phases, and each one phase might use more than one tool. Some of the tools are only suitable to a specific industry and completely irrelevant to others. To maximize tool usage, you should first understand each tool and then determine which ones best fit your needs. Below is a list along with a short overview of the most common tools used in Six Sigma:
- 5 Whys – This method is best used to identify the root cause of the problem. When presented with a defect, formulated questions that will dig deep into the causes of the problem. This is one tool that is applicable to all business settings and even to the ordinary processes in day to day living.
- Accelerated Life testing – This process is more relevant to the industrial setting. This calls for the product to be subjected to the expected and forecasted rigors that it might have to undergo when put to use. Extreme measures and variables are applied in the attempt to uncover any faults and weak points that may cause possible malfunctions.
- ANOVA – This stands for Analysis of Variance. This tool will utilize a set of statistical data. This is often used to gauge the validity of statistic returns of one statistical model applied against another. ANOVA subscribe to the assumption of independence, normality and equality of the responses. With ANOVA R&R, all factors affecting the measurement system are taken into consideration.
- Axiomatic Design – This process is designed to turn established or anticipated needs into products that will address such. This tool uses matrix methods to facilitate step-by-step transition of needs to products and at the same time effectively extracting variables and design limitations as well.
- Business Process Mapping – This is the tool to simplify complex business processes by creating a process flow chart. This is a graphical representation of process flow of responsibility ownership, relationship of individual tasks and organizational alignment. This resembles the organizational chart but with the tasks, roles and process ownership clearly defined. This very effective in streamlining an otherwise dysfunctional and overstaffed organizations.
- Ishikawa Diagram – This process management tool is also known as the cause and effect diagram. This works best during brainstorming sessions. The process will entail the listings of all possible and probable causes that contribute to a defect in the fishbone diagram, thus its second name, fishbone analysis or diagram. The idea of the process is to get the most common problem.
- Cost Benefit Analysis – This method is most applicable if you are comparing two or more courses of action. Monetary valuation is fixed on each attribute and all values, positive for benefits and negative for cost, will be tallied. This calls for a factual assignation of the values taking also into consideration the time value of money. The alternative with the highest monetary value is deemed the most cost effective course of action.
- CTQ Tree – The Critical-to-Quality tree is used to measure the degree of satisfaction a product or a service is able to effective deliver to its end user or customer. The level of satisfaction is derived from the customers’ point of view. Through the use of CTQ, product or service modifications are more effectively aligned to the customer needs.
- FMEA – Failure Modes and Effects Analysis is an effective procedure to forecast and address potential faults and failures of any given process. This tool requires the entire process to be broken down into specific tasks. All possible faults and failures are then listed and will be given severity, occurrence and detection rates. Items that came up highest in the ratings are the most significant faults, thus resources should be focused in addressing that first.
- Histogram – This is another graphical representation that shows data distribution of frequency and density. This is useable in bucketing derived data into bins with specified category and intervals. The interpretation of the graph will be based on the shape or height of the graph as well as the direction of where it is skewed.
- Pareto Analysis – This is another significant Six Sigma tool used in maximizing resources. The Pareto is based on historical data of events and defects. This process subscribes to the idea of addressing the vital few over the trivial many. A list is of all defects observed for a given period of time is listed and their overall contribution is determined. Defects amongst the 80% contribution cutoff, either by count or by weight are considered vital. The analysis is more represented visually by the Pareto chart.
- Scatter Plot – This is also called the scatter graph. This tool uses the Cartesian coordinates to plot values of two given variables from a set of data. Depending on the nearness or closeness of the dots on the chart, we can derive educated conclusions on its correlation, the absence or correlation, the strength of correlation and whether the variables are positively or negatively correlated. This is a tool to use in order to determine the effect of one independent variable to one dependent one.
- Regression Method – This tool is very similar to the scatter plot in the sense that both aim to correlate one variable to another. The main difference is that while scatter plot can only correlate two variables, the regression will be able to identify relationship of one dependent variable to several independent variables.
- SIPOC – SIPOC is the acronym for supplier, or the source of input, input, or the materials needed for the process, process, output, what is produced by the process and customers, the end users of the output. By graphically plotting of all variables that affects the aspects of the whole process, managers are more able to see the bird’s eye view of the process, thus affording a more comprehensive and effective decision making.
Aside from the listed above, Six Sigma also has the following management tools:
- Check Sheet
- Chi-squared Test
- Control Chart
- Design of Experiments
- General Linear Model
- Pick Chart
- Process Capability
- (QFD) Quality Function Deployment
- Quantitative Marketing Research through Enterprise Feedback Management
- Root Cause Analysis
- Run Charts
- Taguchi Methods
- Taguchi Loss Function