The House of Quality (HOQ) is a fundamental tool used in Quality Function
Deployment (QFD), a structured approach to designing and improving
products or services based on customer requirements. The HOQ helps
translate customer needs (WHATs) into specific product or service features
(HOWs) and establishes the relationships between them.
● Customer Needs (WHATs):
These are the starting point of the HOQ. WHATs represent the needs,
desires, and expectations of customers. They are typically gathered
through surveys, customer feedback, market research, and direct
communication
with
customers.
WHATs
are
expressed
in
customer-centric language and are the driving force behind product or
service design.
● Technical Descriptors (HOWs):
HOWs are the features or characteristics of the product or service that are
directly related to meeting the customer needs. These are the actions or
attributes that need to be addressed to fulfill the WHATs. HOWs are usually
determined by cross-functional teams and experts in relevant domains.
● Relationship Matrix:
The central element of the HOQ is the relationship matrix, which
visually represents the relationships between WHATs and HOWs. This
matrix indicates how each HOW affects each WHAT, and the strength
and direction of these relationships. The common legends used in the
matrix are:
●
●
●
●
●
Strongly Positive (+ +)
Positive (+)
Neutral (0)
Negative (-)
Strongly Negative (- -)
Each cell in the matrix is filled with one of these symbols to indicate
the nature of the relationship.
● Importance Rating (Weighting):
The Importance Rating is assigned to each WHAT to reflect its relative
importance or priority compared to other WHATs. It's typically
expressed as a numerical value or percentage. This rating helps
allocate resources and prioritize efforts to meet the most critical
customer needs. These ratings are typically determined based on data
collected from surveys, customer feedback, market research, or other
methods that gauge customer preferences and priorities. The ratings
can be expressed as numerical values or percentages.
● Relative Importance (Normalized Importance):
The Relative Importance represents the normalized importance of each
HOW with respect to each WHAT. It's derived from the relationship
matrix and the Importance Ratings. It helps identify which HOWs have
the most significant impact on fulfilling customer needs. This
calculation normalizes the Importance Ratings and expresses them as
percentages. It helps ensure that the sum of the Relative Importance
values adds up to 100% or 1 (depending on the scale used).
● Target Values and Technical Difficulty:
This part of the HOQ includes information about target values for each
HOW, which represents the desired level or performance of each
technical descriptor. It also includes an assessment of the technical
difficulty or feasibility of achieving those targets. This information
guides the design and development process.
● Interrelationships Between HOWs: TRIANGLE
In addition to the primary relationship matrix between WHATs and
HOWs, the HOQ can also include secondary matrices that show the
relationships between HOWs. These interrelationships help ensure that
the various technical descriptors are consistent and coherent in
achieving the overall product or service objectives.