Here is more on Product based definition from the article. Perhaps the moderator could advise whether it is OK to use this much content from the article. I was not concerned in the previous post as it was just a collection of references.
Product-based definitions view quality as a precise and measurable variable. According to this view, differences in quality reflect differences in the quantity of some ingredient or attribute possessed by a product. For example, high-quality ice cream has a high butterfat content, just as fine rugs have a large number of knots per square inch. This approach lends a vertical or hierarchical dimension to quality, for goods can be ranked according to the amount of the desired attribute that they possess. However, an unambiguous ranking is possible only if the attributes in question are considered preferable by virtually all buyers.
Product-based definitions of quality first appeared in the economics literature, where they were quickly incorporated into theoretical models. In fact, the early economic research on quality focused almost exclusively on durability, simply because it was so easily translated into the above framework. Since durable goods provide a stream of services over time, increased durability implies a longer stream of services - in effect, more of the good. Quality differences could, therefore, be treated as differences in quantity, considerably simplifying the mathematics.
There are two obvious corollaries to this approach. First, higher quality can only be obtained at higher cost. Because quality reflects the quantity of attributes that a product contains, and because attributes are considered to be costly to produce, higher-quality goods will be more expensive. Second, quality is viewed as an inherent characteristic of goods, rather than as something ascribed to them. Because quality reflects the presence or absence of measurable product attributes, it can be assessed objectively, and is based on more than preferences alone.