Data that has been collected directly by the researcher , solely for the purpose of their investigation
Secondary Data
Information that someone else has collected
For example the work of other psychologists that has been published in journals or government statistics
Meta analysis
Researchers combine the findings from multiple studies to draw an overall conclusion
Counterbalancing
With counterbalancing , the participants sample is divided in half , with one half completing the two conditions in one order and the other half completing the conditions in the reverse order