Experiments
Experimental design
a set of procedures used to control the influence of factors such as participant variables in an experiment
Repeated measures design
each participant takes part in every condition under the test,
i.e. each level of the IV
Random allocation
allocating participants to experimental groups or conditions using random techniques
Independent groups design
participants are allocated to two (or more) groups which represent different levels of the IV. Allocation is usually done using random techniques
Matched pairs design
pairs of participants are matched in terms of key variables such as age and IQ. one member of each pair is allocated to one of the conditions under test and the second person is allocated to the other condition
Counterbalancing
an experimental technique used to overcome order effects when using a repeated measures design. Counterbalancing ensures that each condition is tested first or second in equal amounts
Order effect
in a repeated measure design, an extraneous variable arising from the order in which conditions are present, e.g.
a practise effect or fatigue effect.