Validity Flashcards
what is validity?
validity concerns legitimacy and accuracy
refers to whether the data collected in a study represents reality and whether an observed affect is a genuine one
in other words, do the results really reflect how people behave in that everyday life or are the results due to something else such as demand characteristics?
2 types; internal and external
internal validity
refers to validity within the study
a study has internal validity if a researcher is measuring what they’re actually intending to measure
for example, if the researcher is aiming to measure intelligence by measuring the size of the head, it’s like to lack validity as intelligence is not always related to brain size
examples of things that can impact internal validity include….
• investigator effects
• demand characteristics
• confounding variables
• social desirability bias
• poorly operationalised behavioural categories
examples of things that can impact internal validity
investigator effects — anything an investigator does that has an effect on the participant’s performance other than what was intended, such as encouraging participants to try harder
demand characteristics — cues that inadvertently communicate the aims of the study to the participants, such as the Bobo doll in Bandura’s study ‘inviting’ an aggressive response
confounding variables — variables in an experiment that vary systematically with the IV and interfere with the results, therefore we cannot be sure that the IV is what caused the change in the DV so conclusions cannot be drawn
social desirability bias — in a questionnaire, participants may provide answers that do not reflect reality because they wish to show themselves in a good light so do not always answer questions honestly
poorly operationalise behavioural categories — do not allow observers to accurately record reality because the categories are not clear
ecological validity
refers to the ability to generalise the findings from a study to other situations and settings
particularly being able to apply the findings to everyday life
factors that can affect ecological validity
nature of the task given to participants
the environment the participants complete the task in
method used to assess the DV
whether the participants are aware they’re being studied
example of ecological validity in a natural experiment
Rutter et al (2011) conducted a study into the effects of institutionalisation of Romanian orphans
one DV that was measured was intellectual development, assessed using IQ tests
such tests are conducted in a controlled environment and may be quite artificial measures of intellectual development
this may have been a factor decreasing the ecological validity of the findings, meaning the findings may not be completely representative of real life
example of ecological validity in a field experiment
Godden and Baddeley (1975) conducted a study into context dependent forgetting using deep sea divers as participants
the divers had to learn a set of words either on land or in water and then had to recall the word list either on land or in water
the DV was measured by learning word lists which is a rather contrived way to test memory, the task has low mundane realism (i.e. low similarity to everyday life)
the participants were aware that they were being studied, meaning they may not behave naturally — they may want to ‘look good’ (social desirability bias) or they may try to behave in line with the researcher’s expectations (demand characteristics)
assessing validity using face validity
face validity is the extent to which test items look like what the test claims to measure
for example, whether the questions on a stress questionnaire are obviously related to stress
only requires intuitive measurement
assessing validity using concurrent validity
concurrent validity involves comparing the current method of measuring the thing you’re intending to measure with the previously validated method on the same topic
to do this, participants are subject to both methods and their scores are then compared
if a method has high concurrent validity, we would expect people to get similar scores using both methods, thereby confirming the concurrent validity of the current method
improving validity
if the method is judged to have poor face felicity, then the method should be revised
for instance, if it is a questionnaire the questions should be changed so they relate more obviously to the topic being studied
if concurrent validity is low then the researcher should remove parts of the research design which may seem irrelevant and check for concurrent validity again — for instance if it is a questionnaire the questions which may seem irrelevant should be removed
to improve both internal and external validity, a researcher should aim to improve the research design
for example, a double-blind study can be used to prevent participants guessing research aims as neither the person running the study nor the participants know the aims of the study
a researcher could make an environment or task have more mundane realism
mundane realism
refers to how a study mirrors the real world
the research environment will have mundane realism if it realistic and experiences encountered in the research environment are similar to those that occur in the real world
tasks have mundane realism if they are representative of the type of things people experience in real life
for example, testing memory by random word lists is not representative of how memory operates in real life as people rarely have to remember meaningless list of words
external validity
validity after the study
refers to the extent that the findings of the study can be generalised to…
• other people (population validity)
• other historical periods beyond the particular time period of the study (historical/temporal validity)
• other settings (ecological validity)
