DMAIC Guidelines


Are there general guidelines or target durations for each phase of DMAIC?

Knowing that we have fruit salad in our portfolio – apples, oranges, grapes, melons, plus 10 more – are there recommendations on how to generate meaningful guidelines for duration where trying to categorize a project may have a considerable number of characteristics and be quite different?


DMAIC process

Duration is a good metric but in the operational definition you need to add a complexity component.  You are seeing what happens when it is not added.  I have defined complexity as the number of groups/departments that need to be engaged in the project.  A simple example is when IT gets involved, there may be some additional time lags that need to be added so they can do their due diligence.  Likewise if you have a project that involves finance or legal, it will add time to the project.  Organization wide projects take more time than departmental ones so when scoping a project, consider how much longer it will take with more groups needed to be involved.  This may help in your estimates and tracking.

As for general guidelines for DMAIC, what I have told executives and belt candidates is that Define should take about 3 weeks, Measure about 8 -12 weeks (depending on how good your data is).  Analyze 3-4 weeks, depending on complexity and that you have data flowing consistently.  Improve 3-4 weeks depending how quickly you can get the improvement in place, training completed, and process stabilized. Control is generally 4 weeks, just to make sure that everything is running as expected and you can show the magnitude of the improvement.

These are mine but it all depends on the Measure phase and getting the baseline well defined and data flowing.  That is the most critical phase in DMAIC and shortcuts there will impact the project.

I hope this helps.

Jim Bossert

Sr Performance Improvement Specialist
JPS Hospital
Fort Worth, TX

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ISO 9001: 2015 Tools for Auditors and Risk Based Thinking

Mr. Pareto Head and ISO 9001 audit


In addressing clause 4 of ISO 9001:2015 regarding organization context and interested parties, what type of tool (spreadsheet, diagram, flowchart, etc), would you recommend to use to simplify the practice and to give a proper  understanding for auditors ?  I understand that risk evaluation (ISO 9001:2015) should be accomplished not only at a high level of establishing and planning objectives, but also at the processes level. If this is right, could organization use some criteria to select processes to be evaluated?


Thanks for contacting ASQ’s Ask the Experts program.  Regarding your inquiry, your selection of tools such as spreadsheets, diagrams, flowcharts and etc., should be driven by whatever best fits your organization’s context, QMS scope and requirements of interested parties.  However, before proceeding with tool selection to “simplify” practices as mentioned in your inquiry, it is essential that the changes and new requirements of ISO 9001:2015 are fully understood and communicated throughout the organization.  As you know, transitioning from ISO 9001:2008 to ISO 9001:2015 will require much more than providing understanding to Auditors.  The transition process should begin with top management and then flow down to the process owners and others throughout the organization.  If a gap analysis hasn’t already been completed, consider doing so to identify those processes that must be improved to meet ISO 9001:2015 certification requirements.

As you know, risk based thinking (RBT) must be a part of an every organization’s process approach, to ensure risks and opportunities are identified and addressed.  Although RBT is not new, it is a changed approach.  ISO 9001:2015 supports the scalability of quality management systems which allows them to be specific to an organization’s  processes, products, and services.  The landscape of today’s quality management systems has changed.  It’s not a “one size fits all” situation.  For this reason, it’s essential for top management, process owners as well as the QMS Auditors to develop a thorough understanding of ISO 9001:2015 and its requirements.  Also of equal importance is the familiarization of top management, process owners, and Auditors with the principals of risk assessment, management and related terminologies (i.e., ISO 31000:2009).

The effectiveness of future QMS audits will depend upon Auditors that can apply their collective knowledge of ISO 9001:2015, risk assessment, and management requirements, as well as their in-depth knowledge of the industries, processes, products, and systems, audited.  Exemplar Global and other accredited ISO 17024 personnel certification bodies have developed online training courses for the purpose of explaining the requirements of ISO 9001:2015.  Other information about transitioning to ISO 9001:2015 is available on the International Accreditation Form’s (IAF) website at  Click this link to read about the recent publication of ISO 9001:2015

About the second part of your inquiry (item b.), it’s important to be aware that RBT applies to every process that comprises your organization’s quality management system.  RBT should be integrated into your organization’s QMS and product planning processes to ensure risks and opportunities are identified and addressed.

A few key questions to consider include, how will your Registrar verify your organization’s conformance with ISO 9001:2015 requirements?  What is your Registrar’s timeline for transitioning existing clients to ISO 9001:2015 requirements?  What type of support will be provided to assist clients through the transition process?

I hope this helps.

Best regards,


Bill Aston, Managing Director
Aston Technical Consulting Services, LLC
Kingwood, TX 77339
Office: (281) 359-ATCS (2827)

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Sample Size and Z1.4

Data review, data analysis, data migration


My question is if I’m trying to determine the sample size of migrated data to see if it migrated correctly to the target database, is the Z1.4 table applicable to that?

The scenario is data is being transferred from an old system to a new system and I want to do a quality check on the data in the new database to make sure everything was transferred correctly. I’m hoping to use the Z1.4 table to determine the sample size if its applicable. Is it applicable and if not, do you know of other standards that I should be looking into that is more applicable?


The movement of a database from one system to another certainly may introduce errors and it may also carry over errors that already exist. In some cases the move may also find and repair errors, yet that generally is done by design.

So, let’s say it’s just a move and you are checking for any new errors that are introduced.

Since you have access to the entire population, the database, in a before (old system) and after the move (new system) and I’m assuming you do not want to check every entry, instead just a sample, then I would recommend using an hypothesis test approach rather than a lot sampling approach.

A hypothesis test based on the binomial distribution may be appropriate as you are checking field entries to determine if they are correct or not (pass/fail).

You can set a threshold defect rate that you want to check the new system is at least this good or better, or you can measure the old system and compare to the new system – it should be equal to the old system as null hypothesis.

You can find a bit more information about a p-test in a good stats book or online at a short tutorial I wrote at

The Z1.4 standard would require you to artificially define a lot or consider the entire database as one lot. The standard lot testing approach does not provide the control and statistical power of hypothesis testing, thus my recommendation. With the p-test you can define the confidence, defect rate to detect, and sample size to fit your needs concerning ability to make measurements, cost, and risk.



Fred Schenkelberg
Reliability Engineering and Management Consultant
FMS Reliability
(408) 710-8248

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Sampling Schemes

Inventory, Inspection, Review, Suppliers, Supplies


Is there a sampling plan for determining the number of cases to pull in a batch from which you perform the ANSI/ASQ sampling of individual products?  For example: you receive 550 cases with 145 product vials/case.  Is it proper to sample a total of 500 vials from 25 cases (using square root of n+1) or would applying the ANSI/ASQ single level II be more appropriate?  We would then need to pull 500 vials from 80 cases.  Or is there a better statistical method?


There are two ways to answer this. One is to follow the standard and take samples from 80 cases until you get 500. It is assumed that the samples are random so that you do not always take the samples from the same location in the case.  That is following the standard.

The second is that you take a sample from 25 cases in a random manner.  That is fine also.  There are no standards for sampling from cases so either way will work.  Years ago, I developed a sampling scheme similar to what is proposed at the employer I was working with at the time.  Sometimes you have to be creative.

Jim Bossert

SVP Process Design Manger, Process Optimization
Bank of America
Fort Worth, TX

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