HOUSE OF QUALITY

DEFINITION

        Is a diagram, resembling a house, used for defining the relationships between what customer wants from a product’s features and overall performances parameters are most critical to fulfilling those wants.

   Translates customer requirements into quantifiable design variables, called engineering characteristics.

BASIC STRUCTURE OF HOUSE OF QUALITY

CUSTOMER REQUIREMENTS

• Documents a structured list of a product’s customer requirements described in their own words (the Voice of the Customer
•   Also included a column with an importance rating for each customer requirement. The ratings range from 1 to 5.
• Usually gathered through conversations with the customer in which they are encouraged to describe their needs and problems.

COMPETITIVE ASSESSMENT

• Table displays how the top competitive products rank with respect to the customer requirements.
•   This information comes from direct customer surveys, industry consultants, and marketing departments.
•   Generally gathered from customers using questionnaire.

ENGINEERING CHARACTERISTICS

•  Product performance measures and features that have been identified as the means to satisfy the customer requirements.
•  Engineering characteristics are measurable values and their units that are placed near the top.
• Symbols indicating the preferred improvement direction of each engineering characteristic are placed at the top of room 3.

INTER – RELATIONSHIPS

•   Created by the intersection of the rows of customer requirements with the columns of engineering characteristics.
•   Each cell is marked with a symbol that indicates the strength of the casual association between engineering characteristic of its column and the customer requirement of its row.
•  The coding scheme for each cell is given as a set of symbols that represent an exponential range of numbers (e.g. 9, 3, 1, and 0).  

ROOF

• Used to identify where the engineering characteristics that characterize the product, support or impede one another.
• For each cell the question is asked:

Does improving requirements cause deterioration or

improvement in the other engineering characteristic?

Ø  If the answer is deterioration, put a cross or “-”

Ø  If the answer is improvement, put a tick or  “+”

Ø  Different levels of such positive or negative interaction (e.g. strong/medium/weak) can be indicated using different colored symbols