DMAIC Phase 1: Define

Transcription

1 DMAIC Phase 1: Define Objectives of Define Phase During the Define phase of a Six Sigma DMAIC (Define, Measure, Analyze, Improve, Control) project, the project leaders are responsible for clarifying the purpose and scope of the project, for getting a basic understanding of the process to be improved, and for determining the customers perceptions and expectations for quality. Also important are establishing realistic estimates for timeline and costs. All these things will ensure that the stakeholders are all on the same page regarding what is going to be done and how to evaluate the project s progress and ultimate success. In some companies, a great deal of work is done prior to chartering a new DMAIC project, so that everyone involved is already aware of the need for the project and is sure that the project warrants the DMAIC treatment. In other environments, however, confirming that a project is suited for this model is also part of the Define phase. Some things to watch for when assessing a project s suitability for DMAIC: Is data available or easy to obtain? Does leadership support exist for improving this process? Is DMAIC really needed or is this a just do it : a problem with a known solution that should just be implemented? Is the team trying to boil the ocean or is the scope reasonable for chartering as a DMAIC project? Is the process directly related to a key outcome such as profitability, customer satisfaction, or employee satisfaction? Roles and resources also need to be clarified up front to avoid misunderstanding. The Process Owner, Project Leader (usually a Black Belt or Green Belt), and the Sponsor/Champion need to be clear on what is expected from them, how they will communicate, and how decisions will be made. Team members and their supervisors will need a realistic estimate of how long their participation will be needed and how many hours per week they are expected to spend on project work. The key tool for Define is the Six Sigma project charter. It should contain the standard information for a project management charter, such as purpose, scope, roles, budget, and expected outcomes. In addition, it is common practice with DMAIC projects to estimate the timeline for each phase, and to provide basic statistics that are already available and relevant to the project. This data may include the baseline cycle time or satisfaction rate, or even the baseline process sigma if it is already known. Understanding the Process A core tenet of the Six Sigma philosophy is that it is usually the process that needs reworking when performance standards are not being met, rather than the people. Once we understand the process, we will have insight into the causes of inefficiency and frustration so that improvements can be made. Later in the project the process will be examined and mapped in great detail. At this point what is needed is a highlevel understanding of the process. The team needs to be clear on what the process was established to accomplish, and what the outputs are. Also important is clarity on the start and stop points of the process, understanding of who the suppliers to the process and customers of the process are, and a description of the main steps in the process.

2 A tool called a SIPOC is often used for this purpose. The name of the tool stands simply for Suppliers, Inputs, Process, Outputs and Customers, and is a visual representation of each of these things. It may be tempting to assume that everyone already knows what the process is and what is involved, but don t let assumptions play a role in your improvement project. Understanding Customers & Quality The origins of Six Sigma reflect a focus on quality as defined by the customer. Before initiating an improvement initiative or implement process changes, it is crucial that the customers expectations for quality and current level of satisfaction are known. Too often business leaders think that they know what customers want and act accordingly, and the intended results do not manifest. In DMAIC we always let the customers of a process tell us how satisfied they are with the process and its results, we do not take someone else s word for it. The tools for gathering this information are many: existing complaint and contact data, focus groups, interviews, and surveys are common. You may find that data already exists that provides a good picture of customer satisfaction and expectations, but more often it is necessary to take proactive measures to gather additional data. Once data is obtained, it is compiled and evaluated using a variety of techniques. The goal is to establish at least one Critical To Quality measure (CTQ): a customer requirement that is truly critical to the customer, that can be measured, and which can have a specification set that must be met. The process sigma will later be calculated based on the extent to which the process currently meets the specification. The Pareto chart is often used to categorize complaints or reported problems by category, so that the most frequent types can be identified. Market segmentation may be used to take into account major differences in the needs and expectations of different groups, such as wholesale customers and retail customers. An affinity diagram can help the project team group customer comments into categories in a variety of ways to explore how customers view the process and to assess where improvement resources should be directed. And fitting the data to a Kano model can make clear which of the customers needs are in most critical need of improvement. Wrapping Up the Define Phase At the end of the Define phase, the team should have a completed project charter, a high-level process map, and one or more CTQs that will allow data to be gathered in the Measure phase. And in terms of mindset, all team members should have a good understanding of why the project is needed, how it will impact stakeholders, and how the project will proceed.

3 DMAIC Phase 2: Measure Objectives of Measure Phase The goal of the Measure phase of a Six Sigma DMAIC project is to get as much information as possible on the current process so as to fully understand both how it works and how well it works. This entails three key tasks: creating a detailed process map, gathering baseline data and summarizing and analyzing the data. In some cases the process mapping is created first so that information gleaned from it can guide the data collection process. In other cases the general data needs are already known and the two pieces can be worked on simultaneously. Process Mapping Depending on the type of process, a Six Sigma process map may be created using direct input from the individuals who participate in the process, by an observer who monitors and records information about the process, or a combination of the two. The most important aspect of this task it that the goal is to create a map of the existing process, good, bad or ugly. This is not the time to incorporate ideas for what can be done differently. Remember that the start and stop points of the process under study should have been determined as part of the Define phase, so the process mapping effort during Measure should have those same delimiters. For many processes, tracking cycle time provides valuable information, especially when the problem being addressed is related to delays and process duration. If it is relatively simple to obtain basic data on the process time for key steps, that can be helpful at this stage. Also important is capturing any variation in the way the process is performed, for instance at different times, by different groups, or in special situations. Do not assume that the process is always performed exactly the same way. Typically an activity flowchart is used to create a visual depiction of the process. Individual steps are shown in order, with decision points and feedback loops as needed, to describe what occurs. Also of benefit for many projects is a deployment flowchart, which specifically illustrates who is performing each step. An opportunity flowchart can be used to highlight steps that are truly necessary and add value to the outcome, and to separate them from steps that represent waste and inefficiency. Once the process map has been compiled, the project team will review it to glean information about potential contributors to problems and inefficiencies. The team should watch for evidence of missing steps, extra steps, delays and bottlenecks, variation in how certain steps are performed, and anything else that could lead to defects, inefficiency and problems. Data Collection As with other aspects of a Six Sigma DMAIC project, it may be tempting to just jump in and start collecting data, under the assumption that the way to do it is obvious. As with the other steps in the process, the only way to ensure success is to do it systematically; with careful planning. For this reason, a data collection plan is usually the first step in the data collection process. The focus of data collection should be in gathering data that helps to describe the problem, as well as uncovering any factors that provide clues about how, when, where, or in what circumstances the problem occurs or worsened. During planning, the team must not only determine what data to collect, but also ensure that the collection process is valid. In some cases this can be accomplish by establishing clear operational definitions for the measures being tracked; in others a more sophisticated technique such as a Gage R&R analysis is necessary.

4 Remember that during Define, the project team established one or more CTQs representing the customer expectation for quality. The CTQ measures and specifications will be used to calculate a process sigma score for the baseline process, so gathering data on those specific measures is a primary focus at this point in the DMAIC project. Projects may require tracking of primary measures such as conversion rate, customer satisfaction rate or cycle time (process duration) or a plethora of other metrics. Typical related measures include the group performing the process (if multiple teams or groups are involved), the time period when the process is performed or the type of product being created or processed. In most cases it is also important to obtain information on process performance over time. Often technology makes this an easy task, with data automatically being stored on an ongoing basis. In other cases it may take additional work, such as compiling historical reports. Data Analysis Data analysis during the DMAIC Measure phase involves creating graphs and charts that provide a visual representation of the data, including trends over time. The type of data will determine the type of visual tool that is used. A first step often involves graphing the data over time, by using a time series plot or control chart. The role of a time plot is to provide visual information about changes in a process over time, including trends and overall amount of variation. If a grouping factor such as department or product was tracked, it is also beneficial to create a stratified time plot, to see if the overall pattern over time differs for the different groups. A control chart is one of the hallmark tools of Six Sigma. It is both a visual representation and a statistical tool, allowing a determination of which components of variation are inherent in the process (common cause) and which are due to external or specific factors (special cause). For categorical data such as complaints or types of product defect, a Pareto chart can be used to visually display the distribution of data across categories and to determine whether the 80/20 rule applies. Frequency plots and stratified frequency plots also provide insights into the distribution of data and thus the process performance. Calculating Process Sigma The Six Sigma methodology gets its name from the fact that, at a process sigma (a measure of process variation) of 6.0, only 3.4 defects occur per million opportunities (3.4 DPMO). Another way of looking at it is that % of the output would meet customer specifications. Most DMAIC projects do not strive for this level of quality, due to the extensive costs and other tradeoffs involved, especially outside the manufacturing arena. However process sigma is a standard that allows comparison of process performance for different processes. It provides a means of gauging the baseline performance and, ultimately, the improvement that is accomplished through the project. The percentage of process output that meets the customer specification is calculated (directly, or in some cases indirectly, based on normal theory) and used to look up the process sigma in a process sigma table. Wrapping Up the Measure Phase At the end of the Measure phase, the project team should have a detailed process map, detailed baseline data and a calculation of baseline process sigma. Team members should have a clear understanding of how the process is currently done and of the specific problems with the process that may be related to the CTQs.

5 DMAIC Phase 3: Analyze Objectives of Analyze Phase The goal of the DMAIC Analyze phase is to identify potential root causes for the process problem being addressed and then confirm actual root causes with data. Having completed the Measure phase, the project team should have already established a clear problem statement which specifies what the problem is and under what circumstances it occurs. They should have already gathered and analyzed data to establish the baseline performance of the process, relative to the Critical To Quality measures (CTQs) established based on customer input. The question that the Analyze phase seeks to answer is Why is this problem occurring? Another way to ask it is, What is the cause of the problem? It is not possible to make improvements to the process until the causal factors are identified. Potential Root Causes In many cases, clues to the factors affecting performance are already available based on the work that was done in Define and Measure. Perhaps the team demonstrated that the problem is isolated to one group, and they know that group is using older equipment. Or analysis of the process map may have revealed some fairly obvious sources of inefficiency and delay in the process. However, this is not sufficient to confirm what is causing the problem for two reasons. One is that, as in all phases of DMAIC, suspicions and hypotheses must be confirmed with data. Not only must the team confirm that these factors are present, they must also confirm that changes in these factors substantially impact the outcome. The other is that the goal of Analyze is to determine root causes, which requires digging deeper than what is apparent on the surface. Several techniques are employed by Six Sigma project teams to identify potential root causes. One is brainstorming, which is used by team members and, ideally, people involved in performing the process under study, to create a large list of factors which could reasonably affect performance. This list will of course include any factors that were revealed based on the process mapping exercise and the data analysis conducted during Measure. Another popular exercise is the 5 Whys, which involves repeatedly asking Why? until it no longer makes sense to do so. The point is to get past the surface-level answers that are likely to be put forth initially, and to uncover the real underlying issues. Cause and Effect Diagrams Once a list of potential root causes has been compiled, the next step is to organize them in a way that makes it easier to prioritize and assess them. Several tools can be used to accomplish this. The most popular is a fishbone diagram or Ishikawa diagram, which uses a display resembling the bones of a fish to categorize potential causes and illustrate the levels of causation. The main bones are used to reflect high-level categories, such as People, Processes, Technology, and Policies Another option is a tree diagram which can be used to organize the same information. It is preferable if the amount of information is large and hard to organize in a fishbone, or if the project team wants to create it more quickly and

6 does not have access to a tool for creating a fishbone automatically. And some people just prefer the more straightforward presentation. Once the diagram has been created, the project team reviews it to determine which seem to be the most likely potential root causes, and to identify any that seem to have consequences in more than one area. These are good candidates for the validation process. Confirming Root Causes In some cases, sufficient data is available from the Measure phase to conduct cause-effect analyses during Analyze. Often, however, it is necessary to collect new data so that the relationship between the suspected root causes and the effect under study can be evaluated. As in the Measure phase, the methods used to analyze the data depend on the type of data collected. Graphical techniques include scatter plots and frequency plots, while statistical techniques include Analysis Of Variance (ANOVA), correlation analysis, and chi-square testing. In Six Sigma, ANOVA is often used when the output measure is continuous (time and money are typical examples) and the input measures or suspected causes are discrete (categorical). Correlation analysis is used when both measures are continuous, chi-square when both are discrete. Wrapping Up the Analyze Phase At the end of the Analyze phase, the project team should have at least one confirmed hypothesis regarding the root causes of the problem the project aims to resolve. Once the root cause is known, action can be taken in the Improve phase to counter it.

7 DMAIC Phase 4: Improve Objectives of Improve Phase The goal of the DMAIC Improve phase is to identify a solution to the problem that the project aims to address. This involves brainstorming potential solutions, selection solutions to test and evaluating the results of the implemented solutions. Often a pilot implementation is conducted prior to a full-scale rollout of improvements. Identifying Potential Solutions In the first stage of Improve it is important to include the people who are involved in performing the process. Their input regarding potential improvements is critical, and this step should not be completed by the project team alone. In fact, it is wise to maintain communication with those who work on the process throughout any Six Sigma quality improvement project. A variety of techniques are used to brainstorm potential solutions to counter the root cause(s) identified in Analyze. Encouraging participants to challenge rules and assumptions, ban excuses and think like small children can be very effective. For those who prefer a more structured brainstorming exercising, specific techniques are available, but often participants are more than able to produce a substantial list of ideas on their own. It is important during this stage that ideas not be judged nor eliminated. Even an outlandish idea that couldn't possibly be implemented as first suggested may lead to a related idea that is an ideal solution. Similar to other aspects of a Six Sigma project, assumptions about what can or cannot be accomplished should not be accepted without confirmation. Selecting Solutions to Implement As in the prior step, it is a good idea to involve the people who work on the process that is being improved, be included in the decisions regarding which potential improvements to implement. With their help, the project team establishes criteria for evaluating the proposed improvements in an objective manner. Criteria usually include time line for implementation, financial cost, the extent to which root causes are likely to be countered and the overall ease of implementation. Some teams consider other factors such is the amount of buy-in that already exists for each possible change. Not all criteria are created equal, so the team may want to assign weights to each criterion prior to evaluating the proposed solutions against each one. Tools to assist with the evaluation include a priority matrix and a Pugh matrix, both of which use basic calculations and ratings to compare the solutions against each other or against a standard. Occasionally a computer model or other simulation can be beneficial in the evaluation process. The goal of this step is to determine the appropriate solutions to implement using objective means, rather than making a decision based on assumptions or preferences. This is a common theme throughout the Six Sigma methodology.

8 Implementing Improvements Planning the implementation is largely a matter of basic project management. The team needs to plan the budget and time line of the implementation, determine roles and responsibilities, and assign and track tasks. Tools for planning include Gantt charts, planning grids and flowcharts. A deployment flowchart can be created for the implementation process itself, as well as for the new process that will be followed as a result of the improvements being implemented. A data collection plan should be created similar to the one used during Measure, and the same data should be collected. After the data is collected the team will compare the before and after data to determine if the key metrics show improvement. It is often beneficial to use Failure Modes and Effects Analysis (FMEA) before implementing improvements to identify and address potential problems that may arise using the improved process. With this tool, the team lists risks and potential issues, and estimates the likelihood and severity of each one. Then the most critical are identified and the team establishes a plan for minimizing each risk. One aspect of implementing improvements that is often overlooked is the impact of change on the people that are involved in and affected by the process. Basic change management procedures should be followed to smooth the way: communication, seeking input, and ensuring the necessary level of commitment from key players. During the implementation itself, the team should be monitoring the process and act to address any issues that arise. In addition, the data should be reviewed periodically to ensure that appropriate data collection procedures are being followed. Evaluating Improvements For some DMAIC projects, it is appropriate to pilot the improvements before proceeding to a full roll out. The most common piloting options include either making changes only in one group or department or making changes for a limited time period. The benefit of a pilot test is that the project team can ensure the changes result in the desired improvements before a full roll out. In addition, the team can gain insights to allow a more effective implementation during the full roll out. Whether evaluating the pilot results or the full roll out results, a variety of techniques are important for assessing the extent of improvement. Perhaps the most important is recalculating the process sigma, so that it can be compared to the baseline process sigma established earlier. Also common are frequency plots or Pareto charts to show before and after data. And the hallmark tool of DMAIC improvement projects, the control chart, is often employed to show the reduction in variation and improvement in performance. Both before and after data are plotted on the same chart, and the control limits are calculated and depicted separately for the two stages. In all cases, statistical tests are typically used in addition to graphs and charts. The same tests that were used in Analyze can be used in Improve; ANOVA, regression and chi-square testing are common. Wrapping Up the Improve Phase By the end of the Improve phase, the project team has demonstrated that the solutions implemented do in fact counter the identified root causes and thus result in substantial improvement in the CTQ metrics. The new process is in place and the team is ready to create a plan to maintain the gains and close out the project.

9 DMAIC Phase 5: Control Objectives of Control Phase The primary objective of the DMAIC Control phase is to ensure that the gains obtained during Improve are maintained long after the project has ended. To that end, it is necessary to standardize and document procedures, make sure all employees are trained and communicate the project s results. In addition, the project team needs to create a plan for ongoing monitoring of the process and for reacting to any problems that arise. Standardizing and Documenting the Improvements The first step of the Control phase is to document and standardize the improvements that were rolled out during Improve. This takes several forms. The process map of the new process that was created during Improve should be reviewed and updated as necessary to reflect any modifications that may have occurred during roll out. It will be used for training and reference so that the new process will be clear. If many individuals or groups are involved in the process, a deployment flowchart should also be developed to clarify roles and tasks. While a process map is a key component of the documentation of the new process, it is usually also beneficial to have a user guide which spells out the steps of the process and provides rationale. This is particularly important if multiple improvements were made and if the new process is substantially different from the original. Finally, the project team will ensure that everyone involved in the process receives proper training and that effective communication occurs. Training may involve actual classroom learning or may consist simply of distributing the process documentation. This is a great opportunity to confirm that the process map and user guides are effective. Creating a Process Monitoring Plan Perhaps the most critical aspect of Control is establishing a plan to monitor the new process and act when results are not up to spec, so that the project gains will be maintained. It is this component of Six Sigma projects that tends to distinguish them from basic project management methodology, whereby the project is closed out once the improvement is confirmed. The monitoring plan clarifies how the process performance will be continuously monitored, who will be notified if there is a problem and how that will happen and what response is required. The first part of the monitoring plan specifies the metrics that will be tracked to summarize process performance, as well as specifying how and how often they will be tracked. Also be sure to clarify who is responsible for doing it; usually it falls to the process owner. Typically the metrics used during Measure and Improve and established as Critical To Quality (CTQ) measures during Define are appropriate. The monitoring plan also indicates what constitutes satisfactory performance and what should be considered a red flag indicating possible problems. The team should brainstorm potential issues and appropriate responses for each. Again be sure to specify not only what needs to be done but who is responsible for making it happen. A control chart should be continuously updated so that the process owner can watch for process shifts or other signs that there may be a problem with process performance. If the process owner is not well versed in interpreting control charts, the project team should create a reference sheet indicating what the process owner should be looking for. If possible, use an automated process to flag the process owner when performance becomes questionable.

10 Finally, since further change in the process environment is inevitable, the project team should develop a process for updating the new procedures when required. The update process will include updating the process map and user guides, communicating the changes to all involved, and modifying the monitoring plan if necessary to reflect the changes. Common changes that the team should plan for include shifts in employee roles, changes in customer specs and replacements for existing technology.