Has two or more conditions woth different participants in each condition.
1.1 Participants only have to do the task once
and are less likely to become bored or to
work out why/what they are being tested on
is less likely to be obvious to them.
1.2 The same task can be used for
each group - Higher chance of
controlling the independent
1.3 Avoids order affected
This is called counter-balancing.
1.4 Non-equivalence of samples due
to the different conditions.
Short version - Individual differences
1.5 You would need to get twice as many participants as you
would for a repeated measures experiment and where
there is too great a difference between the statistical
variances of independent groups may be be able to
proceed with parametric tests.
The same participants are used in each condition.
2.1 Participants are the same and are
therefore easier to compare each
2.2 You need fewer participants as they will
take part in each condition.
2.3 Is more convenient and time saving than
other designs as more data can be gathered as
everybody does each of the task.
2.4 Practise effects (essentially
order effects) - Participants
may improve with each task
as they are practising what
they are doing.
2.5 There is the possibility of order effects
which would result in fatigue effects as
the partipants may get tired after doing
a certain amount of tasks.
Order effects - Where the participant is able to practise, and therefore gain experience due to the repition of the tasks. This changes their initaial knowledge of how they would complete the tasks, decreasing the validity of the results.
2.6 Demand Characteristics - There is a higher
chance of participants figuring out what they
are being tested on/the aim of the study and
start acting accordingly to what they beilieve
the researchers want te results to be.
3 Matched Pairs
A participant in one condition is matched with a particpant in every other condition as close as possible. This is done as closely as possible via age, race, gender, background, ect.
3.1 Participants only have
to be tested once.
3.2 Differences between the two groups are
reduced, results ae therefore more valid.
(More valid results)
3.3 Helps decrease problems such as individual
differences and order effects.
Extranuous variables - A variable that has occured outside the tudy and may effect the results.
Confounding Variable - A variable that occurs inside the study that may have effected the results.
3.4 Good attempt at controlling the participant variables
and the differences they could cause, allowing the
sample to be representative.
3.5 Lengthy and time consuming process that can be
quite 'wasteful' of participants as a large number of
people need to be tested to find appropriate pairs.