Experimental Design
purpose is to provide a structure for evaluating the cause and effect relationship between a set of independent and dependent variables
true experimental design
-subjects randomly assigned to at least 2 comparison groups- control threats to internal validity
Randomized control trial: Gold standard
- treatment group compared to a control group- establish efficacy of a treatment
Quasi Experimental Design
An experiment that does not require random assignment conditions.
Completely randomized
independent groups
Randomized block design
first classified by an attribute variable then randomizedExample: male and female groups
Single factor design
one-way design- have one independent variable that is being manipulated
Pretest-posttest control group design
- compares 2 or more groups (experimental and control)- both groups are tested prior to and following treatment
two group multi-group pretest-posttest design
does not use a true control group, but rather a comparison group
Posttest- only control group
used when the dependent variable can only be assessed following the treatment condition
multifactorial design
two or more ID, with independent groups randomly assigned to combinations of levels
two-way factorial design
An experimental design involving two IVs in which every level of one variable is paired with each level of the other variable
Three way factorial design
examine the main effect of each independent variable
repeated measures design
An experiment using a within-groups design in which participants respond to a dependent variable more than once, after exposure to each level of the independent variable.
multi-factorial design: two way repeated measures design
involves more than one ID
Single factor design: cross over design
when only 2 levels of an ID are repeated, a cross over design can counterbalance the condition
Single Subject Design
- a research design that requires only one or a few subjects in order to conduct an entire experiment- a repeated measure trial with a small sample
Non- Experimental Research: Exploratory
explores the dimensions and relationships of a phenomenon
Non- Experimental Research: Cohort Study
study that measures variables of a group of people over time
Non- Experimental Research: Descriptive
describes time frame of growth/change / progression through surveys, interviews, etc.
Non- Experimental Research: Normative
establish normal values, guidelines for treatment, diagnosis
Non- Experimental Research: Case-Study
involves characterizing the response of one entity, individual, or situation