participants are allocated to different groups where each group represents on experiemental condition
repeated measures
all participants take part in all conditions of the experiment
matched pairs design
participants matched on some variables that may affect the. then one member is assigned condition A and the other condition B
random allocation
each participant has the same chance of being in one condition as any other
counterbalancing
attempt to control for the effects of order in a repeated measures design. half participants do conditions in on order and the other half in the opposite order
independent groups (evaluation)
weakness: participants in each groups are not the same + less economical than repeated measures
strength: order effects are not a problem + participants are less likely to guess the aim
repeated measures (evaluation)
weakness: each participant has to do at least two tasks (could get tired or bored)
strengths: fewer participantsneeded + variables are controlled
matched pairs
weakness: participants can never be matched exactly + time consuming + expensive
strengths: order effects and demand characteristics are less of a problem
