The Category Development Index (CDI) is a marketing tool used to measure how well a product category is performing in the marketplace. It is calculated by dividing the total sales of a product category by the total number of households that purchase that product category.

A high CDI indicates that the product category is doing well and that there is potential for future growth. A low CDI indicates that the product category may be in decline and that marketing efforts should be focused on reversing this trend.

The CDI can be used to help identify opportunities and threats in the marketplace, as well as to develop marketing strategies. It is important to note, however, that the CDI should not be used as the sole criterion for making marketing decisions. Other factors, such as the overall health of the economy, can also affect a product category’s performance.

The Category Development Index is just one tool that marketing professionals can use to assess a product category’s strength in the marketplace. Other factors, such as market share and brand equity, should also be considered when making marketing decisions.