6-1 Chapter Six DESIGN STRATEGIES

6-2 What is Research Design? A plan for selecting the sources and types of information used to answer research questions A framework for specifying the relationships among the study variables A blueprint that outlines each procedure from the hypothesis to the analysis

6-3 Classifications of Designs Exploratory study is usually to develop hypotheses or questions for further research (see later slides) –Crystallizing research questions Formal study is to test the hypotheses or answer the research questions posed

6-4 Methods of Data Collection (Primary Data) Monitoring, which includes observational studies Interrogation/communication studies –Interview –Survey –Experiment

6-5 Power to Produce Effects In an experiment, the researcher attempts to control and/or manipulate the variables in the study. In an ex post facto design, the researcher has no control over the variables; they can only report what has happened.

6-6 Purpose of the Study Descriptive study tries to explain relationships among variables –Describing phenomena –Discovering associations (relationships, correlations) Causal study is how one variable produces changes in another (see later slides)

6-7 The Time Dimension Cross-sectional studies –are carried out once and represent a snapshot of one point in time –Or use data collected across observed units at one point of time Longitudinal studies –are repeated over an extended period –Or use the data collected over time.

6-8 The Topical Scope Statistical studies attempt to capture a population’s characteristics by making inferences from a sample’s characteristics. Case studies place more emphasis on a full contextual analysis of fewer events or conditions and their interrelations.

6-9 The Research Environment Field conditions (actual environmental conditions) Laboratory conditions (controlled experiment) Simulations: replicating the essence of a process in mathematical models

6-10 A Participant’s Perceptions Usefulness of a design may be reduced when people in the study perceive that research is being conducted Participants’ perceptions influence the outcomes of the research (e.g. placebo effects)

6-11 Exploratory Studies Why do Exploratory Studies? –Exploration is particularly useful when researchers lack a clear idea of the problems Techniques of Exploratory Studies (heavily relying on qualitative techniques) –Secondary data analysis –Experience survey –Focus groups

6-12 Exploratory Studies Continued A focus group is a panel consisting of a small group of people (6-10), lead by a trained moderator. Separate focus groups for different subsets of the population may be desirable Methods –Face-to-face, tele-conference, video-conference, online focus groups. Advantages and disadvantages Two stage design may be necessary

6-13 Causal Studies The essential element of causation is that A “produces” B or A “forces” B to occur Mill’s methods of agreement and disagreement Three types of evidence –Correlation (co-variation) between A and B –Time sequence (A  B) –No other possible causes of B The Post Hoc Fallacy as an error in reasoning

6-14 Causal Studies Continued Causal Study Relationships –Symmetrical (just co-movement) –Reciprocal –Asymmetrical (true causality) Asymmetrical Relationships (p. 167) –Stimulus-Response –Property-Disposition –Disposition-Behavior –Property-Behavior

6-15 Achieving the Ideal Experimental Design Essential –Selection of experiment groups and the control group –Random assignment of subjects to the groups Supplemental – matching the composition of subjects among the groups