Marketing management decisions are based on a number of controllable and non-controllable factors.
Controllable factors are those which can be influenced at the level of the firm. e.g. price of the product, packaging decision, physical distribution, etc. However, there are certain factors which are beyond the control of the firm.
These are called non-controllable factors or environmental factors, e.g. rate of inflation, credit policy of banks, competition, etc.
Therefore, controllable variables become marketing tools, which are constantly shaped and reshaped by marketing managers to achieve marketing objectives.
The combination of variables chosen by a firm to prepare its market offering, is called marketing mix. The main components of marketing mix consists of the four P's, viz product, price, place and promotion.