study at the given time. Theoretical sampling is considered to be purpose driven and it explicitly carries out its function on the basis of an emerging theory. The main focus of theoretical research is to use its development through a constant comparative analysis of data that is gained through theoretical sampling for a better understanding of the theory produced. Theoretical saturation The concept of saturation was first defined in the context of grounded theory as theoretical saturation. In qualitative research the word saturation is extensively used almost interchangeably with data saturation, thematic saturation, theoretical saturation and conceptual saturation. Saturation can be simply defined as data satisfaction. It is when the researcher reaches a point where no new information is obtained from further data. Saturation point determines the sample size in qualitative research as it indicates that adequate data has been collected for a detailed analysis. However, there are no fixed sizes or standard tests that determine the required data for reaching saturation. For example, in many phenomenographic studies, theoretical saturation is often reached after 15 to 30 participants, whereas other methods may require far fewer, or greater, numbers. Example of theoretical sampling An example of theoretical sampling is best described by Glaser and Strauss in the 1960s. It is a memo from their research for “Awareness of Dying”. It explains how the search of data is active throughout the research process as the researcher keeps probing into other relevant theoretical questions- “Visits to the various medical services were scheduled as follows: I wished first to look at services that minimized patient awareness (and so first looked at premature baby service and then a neurosurgical service where patients were frequently comatose). I wished next to look at dying in a situation where expectancy of the staff was great and dying was quick, so I observed on an Intensive Care Unit. Then I wished to observe on a service where staff expectations of terminality were great but where patients might or might not be, and where dying tended to be slow. So I looked next at a cancer service. I wished then to look at conditions where death was unexpected and rapid, and so looked at an emergency service. While we were looking at some different types of services, we also observed the above types of serviced at other types of hospitals. So, our scheduling of types of services was directed by