Term
| Campbell and Stanley’s Shorthand Notation RXO |
|
Definition
R represents randomization, and indicates that a particular group (arm) was randomly selected or randomly assigned.
X indicates a treatment, manipulation, exposure.
O indicates an observation, a measurement, a test |
|
|
Term
| Campbell and Stanley’s Notation NMC |
|
Definition
N indicates that the groups were not equivalent
M indicates that the groups were matched
C indicates that there was a cut-off or pre-selection of the subjects. |
|
|
Term
| Population-related threats |
|
Definition
Sample should represent the entire population
There should be no factors that result in the subjects reacting differently to the independent variable. |
|
|
Term
| Environmental or Experimental threats |
|
Definition
Variables described correctly and precise
Hawthorne/Rosenthal/Pygmalion Effects |
|
|
Term
| Campbell and Stanley’s Notation M,X(0),N or dashed line |
|
Definition
M indicates that the groups were matched
X0 indicates that no treatment was given: usually indicates the control group
N or a dashed line ---------------- between groupsindicates non-equivalency, and that there may be significant differences between the groups. |
|
|
Term
| Campbell and Stanley’s Notation C |
|
Definition
| C indicates that the groups are assigned using a pre-selection by cut-off score. |
|
|
Term
| Campbell and Stanley’s Notation C |
|
Definition
| C indicates that the groups are assigned using a pre-selection by cut-off score. |
|
|
Term
| Pre-experimental Designs. |
|
Definition
X O
These are considered the weakest of the research designs
There is no control group for comparison purposes.
There is no pre-test for comparison purposes.
Some refer to this as a Non-experimental Design |
|
|
Term
|
Definition
|
|
Term
| “Natural Experiments” or “Experiments of Opportunity” |
|
Definition
| Are events (exposures) (the “X” in Campbell and Stanley’s notation ) - occurring outside controlled settings, and could never be deliberately caused or induced: |
|
|
Term
| What is the main weakness of pre-experimental designs? |
|
Definition
|
|
