Definition of research design
A research design refers to a master plan, blue print and even a sequence of research task activities. Research design in simple terms is a plan of methods and procedures that is used by researchers to collect and analyze data needed by the manager. They also contain clear objectives, specify information sources on which the data will be collected, the type of data, design technique, sampling methodology and budgets as well. The three types of research design are namely exploratory, descriptive and causal research design.
Exploratory research design
Exploratory research design is a study which is designed to find out enough about the problem to usefully formulate a hypothesis. It stems from the general problem description such as finding out how consumers make decisions about things like life insurance. Exploratory research design is used when looking for insights into the problem and also to help define hypothesis (but does not test) and key variables. It is also used to identify course of action when information needs are vague and also to establish priorities for further research.
Characteristics of exploratory research design Exploratory research design is flexible and unstructured
It is used for finding tentative data
Used as building block for more research. For example pilot surveys, secondary data and focus groups
It is done on small non representative sample
Methods used
Exploratory research design uses soft methods such as depth interviews, focus group discussion, case studies, qualitative research and also secondary data.
When it is done
It is done generally initial research conducted to clarify and define the nature of the problem.
Descriptive research design
Descriptive research design describe something as the name entails. For example it may describe the target market population characteristics proportion of users and also predict future demand. Descriptive research studies lie between exploratory and causal research design. These studies assume that the relevant values are known and hypothesis is of the general type. Results tend to be profiles of customers versus those who are not customers. It is often used as a follow up to exploratory research
Characteristics
It is more rigid than exploratory
The problem is well understood
It test a specific hypothesis It is formal and structured
It has large representative sample
Also provides a snap shot of the market environment
Methods used
Descriptive research design uses methods such as surveys, panel data, observations and mostly quantitative data
Causal research design
It is the most demanding type of study. They assume that not only do we know what the relevant variables are, but that we can hypothesize how they affect each other. The issues that are important in causal research design are that conforming of disproving the hypothesized relationships and that if the hypotheses are so specific that the mathematical form of the relationship between the variables is known. If mathematical form is known estimation of the parameters and strength becomes possible. The objective if causal research design is to obtain information regarding cause and effect relationship. It is used to understand which variable are causes and which variables are the effects.

Characteristics Independent variables manipulated in a relatively controlled environment
Methods
The method used for causal research design is experiments. It is the main method and is divided into two which is laboratory and field experiment.
b)The differences of the above influence relative importance of each research approach at each phase of the marketing research process in that the emphasis of exploratory research design is on discovery of ideas and insights, that of descriptive is frequency of occurrence and the emphasis of causal is of determining cause and effect and thus their differences influence relative importance at each phase of the marketing research approach. At the first stage of the marketing research process which is problem formulation, the research approach that is used is exploratory research design because it is used to look at the insight of the problem and the problem formulation stage entails defining a problem and distinguishing a problem symptom from a problem situation thus the differences of the research approaches influence relative importance at each phase of the market research process
Another difference of the research approaches which influence relative importance at each phase of the market research process is the different methods that are used. The exploratory uses focus groups and depth interviews whilst descriptive uses surveys, observations and panel data and the causal uses experiments. Thus at the second stage of the research process which is determination of the research design exploratory, descriptive and casual are used.
Exploratory research design is generally found to be qualitative and hence used when identifying a problem and whereas descriptive and causal are quantitative and hence is suitable for tabulation and analysis phase which is rigid.

REFERENCE LIST
Don W. Stacks, Primer of Public Relations Research.Guilford Press, 2002
Green P. E Tull DS, Albamm G (1993) Research Methods for marketing decisions, 5th Edition, Prentice Hall
Joselyn R. W, Designing the market research, Pretocellis Charter, New York
McQuarrie Edward F, The Market Research Toolbox: concise for beginners
Wayne C. Booth, Gregory G. Colomb and Joseph M. Williams 2008, The Craft of Research, University of Chicago Press