Types of research designs (see also Cases 2-1 to 2-4)
Appropriate research design for a study depends on how much is known about a phenomenon
Exploratory research - When little is known; Way of getting ideas, insights, understanding research problem
Descriptive research - When enough is known to ask specific questions about a phenomenon; To test hypotheses about relationships between variables; To obtain descriptive information
Causal research - When enought is known to specify the cause & effect; To test the causality - the most detailed type of knowledge that can be obtained through research
Each type of research is a progression in gaining knowledge about a phenomenon & a research project may involve more than one phase
Exploratory research - Focus groups; Literature search; Experience surveys, etc.
Descriptive research - Cross sectional versus longtitudinal
Causal Designs (see also Cases 2-5 to 2-7)
Evidence for causality Concomitant variation; Time order of occurrence of variables; Elimination of other possible causal factors
Experiments - An experiment is a design that aims to assess causality
Types of experiments - Lab versus field
Criteria for evaluating experiments - Internal versus external validity
Extraneous variables in experiments that should be minimized/eliminated: History; Maturation; Testing; Instrument variation; Statistical regression; Selection bias; Experimental mortality
Specific Designs: Preexperimental designs
One Shot case study - X O
Problems: History, maturation, selection, mortality
One-Group Pretest Posttest - O X O
Problems: History, maturation, testing, instrumentation, regression (?), interactive testing
Static Group Comparison - EG X O1 CG O2
Problems: Selection, mortality, maturation (?)
Specific Designs: True experimental designs
Before-After with Control Group
EG: (R) O1 X O2
CG: (R) O3 O4
O2 - O1 = E + U + I
O4 - O3 = U
(O2 - O1) - (O4 -O3) = E + I
Problems: Interactive effect of testing
Four Group Six Study
EGI: (R) O1 X O2
CGI: (R) O3 O4
EGII: (R) X O5
CGII: (R) O6
O2 - O1 = E + U