# Brand and Category Development Indices

Subject: Advertising and Public Relations

Exam: TEE

Reader: https://deep-learning-study-room.vercel.app/apr/#tee/formulas/facts/indices

Canonical: https://deep-learning-study-room.vercel.app/read/apr/tee/formulas/facts--indices/

M2 and TEE · media measures

BDI/CDI concepts and four high/low interpretations are confirmed PYQ topics. The numerical values in the examples below are authored illustrations; the recovered questions do not supply data to calculate.

## Formula



$$
\operatorname{BDI}=\frac{\%\text{ of national brand sales in area}}{\%\text{ of national population in area}}\times100
$$



Both inputs are percentage shares with the same geographic boundary and time basis. BDI concerns one brand; CDI uses the whole product category. An index of 100 is average representation, not 100% local penetration.



$$
\operatorname{CDI}=\frac{\%\text{ of national category sales in area}}{\%\text{ of national population in area}}\times100
$$



| BDI | CDI | Interpretation |
| --- | --- | --- |
| High | High | Brand and category over-represented: consider sustaining strength. |
| Low | High | Category strong, brand relatively weak: investigate distribution/positioning/competition. |
| High | Low | Strong brand concentration in a weaker category: assess profitable maintenance. |
| Low | Low | Both under-represented: investigate causes before committing or withdrawing. |

An index of 100 is the average benchmark. These combinations are diagnostic clues, not guaranteed investment rules.

#### Illustrative example · Read the calculation in words

If an area has 12% of national brand sales and 8% of the population: BDI = 12 ÷ 8 × 100 = 150. The brand is 1.5 times as represented in sales as in population.

## Complete worked solutions

- [Optional authored drill 1](https://deep-learning-study-room.vercel.app/read/apr/tee/practice/numbers--indices1/)
- [Optional authored drill 2](https://deep-learning-study-room.vercel.app/read/apr/tee/practice/numbers--indices2/)
- [Optional authored drill 3](https://deep-learning-study-room.vercel.app/read/apr/tee/practice/numbers--indices3/)
- [Optional authored drill 4](https://deep-learning-study-room.vercel.app/read/apr/tee/practice/numbers--indices-counts/)