A variation is to divide the area into "parcels" of land. Generally, statisticians criticise the method for its theoretical weakness while market researchers defend it for its cheapness and administrative convenience. However, the convenience seriously jeopardizes the reliability of the data obtained.
If the area is large, it can be subdivided into sub-areas and a grid overlayed on these. Here are some of the common probability techniques that are widely accepted and used by most modern organizations.
Exploratory research: This sampling technique is widely used when researchers aim at conducting qualitative research, pilot studies or exploratory research. Clusters are identified and included in a sample on the basis of defining demographic parameters such as age, location, sex etc.
Market research, when done properly, is often the difference between good and great outcomes.