Transcript Strengths and Weaknesses of Psychological research that is reliable

Assessment for Learning:
AO2: assess the validity,
reliability and credibility of
scientific information.
Learning Aims:
Understand the concepts of Validity
and Reliability in Psychological
Research
Reliability
This measures consistency from one occasion to another – the
same result should be found on different days, in different labs ,
observations or interviews, by different researchers
How would you assess the external
reliability of a questionnaire?
What about by different researchers?
Participants take the same test on different occasions – a high correlation between test
scores indicates the test has good external reliability .
Timing is crucial. Why?
I hope that’s
the right
answer this
time
January
June
Consistency between
different researchers
working on the some
study is very important
for reliability
In observational studies
this is known as interobserver reliability –
observers have to agree
on what they see and
carry out the same
procedure
This measures the extent to which a test or procedure is
consistent within itself, i.e., questionnaire items or questions in
an interview should all be measuring the same thing
Do you like to keep to deadlines?
Do you get impatient driving?
Do you like cheese?
Do you like doing several tasks at once?
Do you like chocolate?
Do you get easily irritated?
Are you competitive?
This interviewer seems a
little confused about
Type A personality traits
This measures the extent to which a test or procedure is
consistent within itself, i.e., questionnaire items or questions in
an interview should all be measuring the same thing
How would you assess the
internal reliability of a
questionnaire measuring stress?
Have a go!!
Do all the questions
address stress or do they
measure something else?
Odds/Evens
Top/Bottom
This refers to the
of a researcher’s behaviour.
A researcher should produce similar test results, or make similar observations or carry
out interviews in the same way on more than one occasion.
Thanks for taking
part today. Any
problems and I’ll be
right over. Take
your time.
How much longer
before I can get in
the pub and relax my
facial muscles?
Right. Let’s get on.
Fast as you can.
Improving Reliability
1.
2. Carry out a pilot study
to improve procedures
a) What would you add to your definition on slide 4
to make it four marks?
B) Describe two pieces of research that are reliable:
•Think about: Standardised Controls – blind studies, designs,
equipment
C) Describe two pieces of research that lack reliability:
• Think about: Self reports - Low inter-rater reliability - reliability of self
reports may be affected if different interviewers ask questions in different
ways or the same interviewer behaves differently on different occasions.
•Think about: Qualitative data, case studies
Strengths and Weaknesses of Psychological research that is reliable:
In your pairs, write an effective paragraph on one of the following
points:
•More standardised the better the controls, the better the controls the
more reduction in confounding variables, the more control over
confounding variables the higher the internal validity
•More consistency – replicibility
•Consistency does not mean validity – are you measuring what you
set out to measure?
•Standardised procedures mean low ecological validity
Using your understanding of the issues in diagnosing
individuals with disorders, can you describe a
scenario to explain the following terms:
High Inter-rater reliability
Test-retest method
Low Inter-rater reliability
Lacks reliability
•qualitative data - often the therapist’s subjective opinion, which
may mean that the diagnosis is unreliable. For example, Thigpen
and Cleckley took a psychodynamic approach to diagnosis but there
may have been a physiological cause for Eve Black’s symptoms.
•Furthermore Freud took a psychodynamic approach and only
looked for evidence to support his theory of psychosexual
development.
Check understanding!
Derek has been to see Dr Padawi who diagnoses OCD; Dr
Padawi asks Dr Ahmed to also see Derek to see what she
thinks; she also diagnoses OCD
Mary is referred to Dr O’Leary who diagnoses bi-polar
disorder; she asks to see her in eight weeks time and reassess Mary; Mary still appears to have bi-polar.
Maureen sees three doctors as she has a complex variety of
symptoms; none of them can agree; one thinks she has
OCD, another says she has PTSD and another says she has
depression