A rolled throughput yield is a percent that measures the probability that a unit can "roll through"  a process without defects.  The rolled throughput is calculated by determining the throughput yield (first pass yield, first time yield) of each process step and then multiplying those throughput yields (first pass yield, first time yield) by each other in order to obtain the cumulative or "rolling" throughput yield.  This measure takes into account rework and scrap providing an organization with a more accurate assessment of internal waste and or hidden costs.  

The average or ratio of the number of defects per unit observed during an average production or service run divided by the total number of opportunities to make a defect on a product or service normalized to the number 1,000,000.

Calculating DPMO

​-To Calculate DPMO from DPO simply multiply DPO by 1,000,000.
- To Calculate DPMO from DPU - DPU/(opportunities/unit) x 1,000,000.

  ​The seven basic quality tools are a set of tools that are used to help organizations understand and improve their business processes. 

  Defects per opportunity is a common metric that can be used to indicate the number of defects in a process or product per opportunity.  It is calculated by dividing the total number of defects in the sample lot or batch by the total number of opportunities.

Example

A team determines that each shirt can have 10 opportunities for defects we have 500 shirts in our sample lot.  This gives us 5,000 opportunities (10 opportunities x # in sample batch) for a defect to occur.  The inspector observed 50 defects in the sample lot.  Making our DPO .01 (50 divided by 5,000).  To learn more visit our recent blog post on Listen to the Gemba entitled Calculating Defects Per Opportunity (DPO).

  The total cost of ownership is the sum of all the costs associated with every activity of the product or service.  The benefit to using total cost of ownership is that it provides us with a deeper look and a better understanding by which we can base our decisions on.  For a free make or buy comparison template click on the link below.

  A Kaizen event is a set of activities usually over a predetermined time which is carried out by a team, department or organization for the purpose of improvement.

  Quality Function Deployment is a methodology developed by Dr. Yoji Akao.  The methodology attempts to accomplish all major requirements of the customer.  It does this by identifying the voice of the customer and working to ensure the needs are met or exceeded.  QFD is also often viewed as a set of communication and translation tools.  QFD tries to eliminate the gap between what the customer wants and what they get.  

  A defective unit is an item or service that is considered to be unacceptable for use.  Every item is either defective or not.  A defect is not the same thing as defective.  The main difference is that a defect may be considered okay for use, however a defective unit has been deemed unacceptable.  

  The change control process is a sequence of steps which are used to control changes within an organization.  


Example of Change Control Process:

1. Document the change request.
2. Determine if the change is valid through assessment.
3. Approval or reject of change.
4. Planning.
5. Testing of Change.
6. Implementation of Change.
7. Validation through assessment of the changes new state.

Recommended Reading:  

• Engineering Documentation Control Handbook, Fourth Edition: Configuration Management and Product Lifecycle Management

  Variation is the term used to describe the consistency of a processes outputs.  Reducing variation is one of the most important objectives in Lean and Six Sigma.  The reduction of variation improves sigma rating and creates more stable processes that can be improved upon.  There are two types of variation: Common cause variation and Special cause variation.

  The SIPOC map is a map used to identify systems and processes at a high level.  The map shows material and information flow in forward and backwards loops, this allows teams to identify potential gaps from a systemic view which helps us understand the effects of activities both upstream and downstream.  The mnemonic SIPOC serves as a reminder that this powerful map shows us suppliers, Inputs, Process, Output and Customers.  

  Process mapping refers to a tool used to make business processes visual.  The process map documents an entire process step by step.  The process map is generally used towards the beginning of initiatives in order to understand the flow of a process but it can also be used in support of almost every phase of improvement projects.  

  Hypothesis testing is a statistical test that is used to determine whether or not there is enough evidence contained within sample data to confirm a condition.  The hypothesis test looks into two types of tests null and alternative.

  Activity based costing (ABC) is a system used in accounting that identifies costs based on activities performed.  The system then uses the drivers of cost (indirect and direct) to allocate or reserve costs to products, projects, customers or other segments.  The system attempts to allocate costs like overhead on a more accurate basis than simply assigning direct labor or machine hours which may change from product to product.