Psychological Research and
Scientific Method pt3
Designing psychological
investigations.
Selection & application of
appropriate research methods.
What is my hypothesis
(directional/non-directional?
What is my research aim?
Should
I use quantative or
qualitative.
Key considerations when designing
psychological investigations.
1.
Choosing an appropriate
research method.
2. Deciding upon the amount of
Ps.
3. Using appropriate sampling
method
4. How to debrief Ps.
5. How should I record the
data & the techniques to be
used.
1. Is the data qualitative or
quantative, if the former =
transcripts, if the latter =
experiment.
2. Consider finances &
practicalities.
3. Target population should be
identified & a representative
sample should be used.
4. Need to always consider
ethics...is deception
necessary? Should they know
you are there (observations!)
5. Number analysis, Written
record, video of interviews, a
combination? How should it be
coded? Should results be
omitted?
Pilot study….why is this
necessary?
• This is an important step in designing a good
research study. It is characterised as
• ‘A small scale trial run of a specific
research investigation in order to test out
the planned procedures & identify any flaws
& areas for improvement’.
• It provides feedback to clear up any issues.
The relationship between
researcher & participants.
Studying complex behaviour can create several ‘social’ type issues that
can effect the outcome of the investigation such as
1.
Demand characteristics: Behaving in a way that they perceive
will help or distort the investigation.
2.
Participant reactivity: Faithful/faithless, evaluation
apprehension or social desirability bias. Change in behaviour because you
think you are being evaluated in a positive/negative way (try harder/not hard enough!)
3.
Investigator effects: Undesired effect of the researcher’s
expectations or behaviour on participants or on the
interpretation of data.
So I don’t have to retype it!!!!!
• See AS Research methods for information on
experimental design
• Extraneous variables
• Methodology
• Ethics
• Sampling techniques.
• You should be able to identify, explain and
give at least two advantages & two
disadvantages of all the above!!!!!!
Issues of reliability & validity.
Types of reliability
1. Internal: Consistency of measures, no lone ranger
gets in and messes with the investigation!
2. External: Consistency of measures from one occasion
to another- Can a test be relied upon to generate same or similar results.
3. Research Reliability: Extent to which researcher
acts entirely consistently when gathering data in an
investigation. Aka experimenter reliability in experimental conditions &
inter-rater/inter-observer reliability.
Assessing researcher reliability.
(Intra)
• Intra researcher reliability is achieved of the
investigator has performed consistently.
• This is achieved when scoring/measuring on
more than one occasion and receiving the
same or similar results.
• If using observations or other non
experimental methods this is achieved by
comparing two sets of data obtained on
separate occasions and observing the degree
of similarities in the scores.
Assessing researcher reliability.
(Inter)
• Researchers need to act in similar ways.
• All observers need to agree, therefore they
record their data independently then
correlate to establish the degree of
similarity!
• Inter observer reliability is achieved if there
is a statistically significant positive
correlation between the scores of the
different observers.
Improving researcher reliability
• Variability brings about extraneous variables
so it is important to ensure high intra-inter
research reliability by:
• Careful design of a study- E.g. Use of piloting, as
this can improve the precision and make the
investigation less open to interpretation.
• Careful training of researchers- In procedures
& materials so variability can be reduced among
researchers. Operational definitions should be used
and understood by all and researchers should know
how to carry out procedures and record data.
Assessing & improving internal &
external reliability.
• Split-half method: Splitting the test into two parts
after data has been collected. The two sets of data
are then correlated, if the result is statistically
significant it indicates reliability. If not significant
each item is removed & retesting occurs. The overall
aim is to reach +.8 & reach internal reliability.
• Test-retest method: Presenting same test on
different occasions with no feedback after first
presentation. Time between is important too, cant be
too short/long! If statistically significant between
scores this is deemed as stable, if not items are
checked for consistency & reliability retested if
correlation can be obtained.
Techniques to assess & improve internal
validity.
•
Face validity: On the surface of things, does the investigation test
what is claims to be testing!
•
Content Validity: Does the content of the test cover the whole topic
area? Detailed systematic examination of all components are measured
& until it is agreed that the content is appropriate.
•
Concurrent validity: When the measures are obtained at the same time
as the test scores. This indicates the extent to which the test scores
accurately estimate an individual’s current state with regards to the
criterion. E.g. On a test that measures levels of depression, the test would be said to have concurrent
validity if it measured the current levels of depression experienced by the participant.
•
Predictive validity: occurs when the criterion measures are obtained at
a time after the test. Examples of test with predictive validity are
career or aptitude tests, which are helpful in determining who is likely
to succeed or fail in certain subjects or occupations.
Just a little extra on ethics!
There are several ethic committees:
1. Departmental ethics:-The DEC carries out
approval on undergraduate & postgraduate
proposals. At least 3 members should be
involved who do not have an invested
interest in the research but have the
appropriate expertise to look over the
proposal. They yeah/nay the proposal ask
for modifications if they deem it to be
necessary. They may refer the proposal to
the IEC if researchers are needed from
other disciplines.
Institutional ethics (IEC)
• Formed by Psychologists and
researchers from other disciplines.
• They have a wider expertise & practical
knowledge of the possible issues (law or
insurance.)

•
• The chair of the IEC will yeah or nay or
ask for resubmission upon modification
External ethics committee (EEC).
1. Some research cannot be approved by either the
DEC or IEC and will need the EEC.
2. This is likely to be the case for proposals involving Ps
from NHS etc..
3. The ‘National research ethics service’ (NREC) is
responsible the approval process.
4. The EEC consists of experts with no vested interest
in the research.
•
Monitoring the guidelines serves as a final means of
protecting Ps. If Psychologists are found to be
contravening guidelines they can be suspended or
have their license to practice removed or expelled
from the society (BPS).
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Psychological Research and Scientific Method pt3