NEEDS,WANTS,DEMANDS:
Marketing thinking starts with the fact of human needs and wants. People need food, air, water, clothing, and shelter to survive. Beyond this, people have a strong desire for recreation, education and other services. They have strong preferences for particular version and brands of basic goods and services.
Need:
A human need is a state of felt deprivation of some basic satisfaction. People require food , clothing , shelter , safety , belonging , esteem , and a few other things for survival. These needs are not created by their society or by marketers; they exist in the very texture of human biology and the human condition.
Want:
Wants are desires for specific satisfiers of these deeper needs. Human wants are continually shaped and reshaped by social forces and institutions , such as churches , schools , families , and business corporations.
Demand:
Demands are wants for specific products that are backed by an ability and willingness to buy them. Wants become demands when supported by purchasing power. Many people want a Mercedes car ; only a few are able and willing to buy one. Companies must therefore measure not only how people want their product but , more important , how many would actually be willing and able to buy it.