Contextual Design is a user-centered design process developed by Hugh Beyer and Karen Holtzblatt (1998). It incorporates ethnographic methods for gathering insights relevant to the product, field studies, rationalizing workflows, system and designing human-computer interfaces. In practice this means that researchers aggregate data from customers in the field, where people are living and applying these findings into a final product.

Contextual inquiry involves collecting detailed information about customer work practice by observing and talking with the user about the work while s/he works, in the normal context of the work. The researcher ought to stay on the background and let the user lead the situation as much as possible. This means that the researcher tries to form a partnership with customer i.e. learning (but not doing) as an apprentice while the customer is the master of the work. This helps the researcher to understand the customer’s work. The goal is to understand how and why something is done or why something is not done. (Beyer & Holtzblatt, 1998)

Personas are user models that are presented as specific individual humans. They are not actual people, but are synthesized directly from observations of real people.
(Cooper. About Face 2.0, pp 55-74 X)

Personas are archetypical users with specific goals and needs based on real market and design research.
(Laurel. Design Research, MIT Press, 2003. p 75)

Scenarios are paradoxically concrete but, rough, tangible but flexible, they implicitly encourage “what-if?” thinking among all parties. They permit the articulation of design possibilities without undermining innovation. Scenarios compel attention to the use that will be made of the design product. They can describe situations at many levels of detail, for many different purposes, helping to coordinate various aspects of the design project.

(Carrol. Making Use: Scenario-based Design of Human-Computer Interaction)

Focus Groups are a social science tool used prevalently to conduct market research. Focus groups are discussions with a limited number of participants, led by a moderator.
(A Designer’s Research Manual, Visocky O’Grady, p640, 2006)

“Survey research is a tactic for collecting quantitative information by asking participants a set of questions in specific order. Questions are administered to a sample of individuals, representative of a larger population.”(Visocky O’Grady. A Designer’s Research Manual. p 48)

Task analysis analyses what a user is required to do in terms of actions and/or cognitive processes to achieve a task. A detailed task analysis can be conducted to understand the current system and the information flows within it.
“Task Analysis”. UsabilityNet. 2006. http://www.usabilitynet.org/tools/taskanalysis.htm

“Arranging for a product to occupy a clear, distinctive and desirable place relative to competing products in the minds of target consumers. Formulating competitive positioning for a product and a detailer marketing mix.” (Kotler. Principles of Marketing, p 31)

“Dividing a market into distinct groups of buyers with different needs, characteristics or behaviour who might require separate products or marketing mixes.” (Kotler. Principles of Marketing, p 31)