Voice of the Customer (VOC)

The customer may specify only one specification limit and the target value is not necessarily the midpoint of the specifications. Don't assume this value, ask the customer for the target value if one exist.

The VOC may also involve attribute specifications such as a "number of ...", color type, or PPM rating.

Objective:

Successfully obtaining the needs of customers, lost, current and potential. It is imperative to know who they are first before getting more elaboration into the numbers. Some will be obvious due to history and others are unknown but potential customers. The customers are also the employees and your company.

This sounds easier than it is and is often based on tribal knowledge and intuition of “experts”. Take nothing for granted during this critical research period. Spending ample time obtaining the information completely along with their specification and perception of quality is often the most difficult of this phase.

Some customers may have very specific needs that conflict with other customers or some needs may be to specifically meet the needs of one or a few people at a customer’s company. Understanding these needs at that level of detail is necessary to guide the team in the right direction. Proper time spent on this step will avoid targeting wrong or lower importance needs of the customer.

The Voice of the Customer will provide the upper specification limit and/or lower specification limit and/or a target for each CTQ (requirements in the CTQ Flowdown and SIPOC.

IMPORTANT:

The VOC provides specification limits (LSL. USL). This is NOT the same as the VOP which provides the control limits (LCL, UCL). The VOP describes the width of the data and can change with every new data point, in other words the LCL and UCL are formulas whose values are changing to describe the process behavior. The specification limits (VOC) are constants, unless the customer informs of a change.

The VOC will be refernced and verified throughout the project and ultimately at the closing of the project and hand-off to the Process Owner.

Sources of the Voice of the Customer are:

Surveys

Past complaints

Service issues

Quality issues

Delivery issues

Customer scorecards

Interviews

Marketing research

Data studies of patterns and trends

Audits

Past decision behavior and tendencies

Technology research

Focus Groups

Customer needs, wishes, desires, mandates, attitudes are dynamic. Keeping up with trends and predicting behaviors separates the best and better products, processes, and services. Although it is very important for any Six Sigma project, it is especially important when developing an unprecedented product or process in a DFSS project. The more that can be obtained the better. Be cautious on the approach and strategy, delicately balancing the team's desire to obtain all possible information without annoying the customer, leaking a potential competitive edge, or tying up to many resources.

Categorizing the customer needs is done by using an Affinity Diagram and prioritizing them is done using Quality Function Deployment.