Research methods notes
What is an aim?
a general statement of what the researcher intends to investigate- purpose of the study.
‘to investigate…’
What is a Hypothesis?
a clear precise testable statement that states the relationships between the variables to be measured. Stated
at outset of the study. Can be directional or non-directional.
Directional hypothesis (one-tailed) – states the direction of the difference or the relationship.
o researchers use directional hypotheses when findings of previous research suggest a
particular outcome
o “People who … will be more…than those who...”
Non-Directional hypothesis (two-tailed)- states there is a difference between conditions but does not
specify the direction.
o Researchers use non-directional hypotheses when there is no previous research or findings
are contradictory
Null hypothesis
states there is no difference between conditions or co-variables.
Alternative hypothesis
states that there is a relationship between the two variables being studied
Directional alternative hypothesis(one tailed): specific about effect that IV will have on DV e.g. ‘girls
will score higher than boys in A level
Non-directional alternative hypothesis (two-tailed): Say IV will affect DV but not specific about how
this will be e.g. ‘a significant difference in A level scores of boys’ and girls’
Which one to pick? (directional or non-directional)
Directional = sufficient background evidence (previous research)
Non-directional = if evidence is unclear + researcher wants to suggest they are avoiding bias
,Types of variables
Independent variable - changes or is manipulated so the effect on the DV can be measured.
Dependent variable - measured by the researcher.
Extraneous variables
any variable, other than IV, that may influence the DV if it is not controlled.
these are identified at the beginning of an experiment to have their influence minimised.
Do not vary systematically.
Confounding variables
any variable, other than the IV, that may have affected the DV so we cannot be sure of the true
source of changes to the DV.
Vary systematically with the IV, e.g. personality.
Should have been controlled
Operationalised variables
clearly defining variables in terms of how they can be measured
Each variable should be operationalised in order to make the hypothesis clear and testable
Types of experimental method
Experimental method involves the manipulation of an IV to measure the effect on a DV.
Experiments may be laboratory, field, natural, or quasi.
Dependent on:
o How much control we have over IV
o How much control we have over extraneous variables
Experiment and variables
One variable kept constant
Another measured to see if it changes (IV) relative to the variable manipulated by experimenter (DV)
Establish a causal relationship between variables
,Lab experiments
Occurs in a controlled environment using standardised procedures and instructions that allows high
degree of control over extraneous variables e.g. skinners box
Controls variation of IV and measures change of DV
Participants can be randomly allocated to the conditions to control for participant variables. Material and
stimuli can also be randomly allocated
Participants are aware they are taking part in the experiment; however they may not know the true aims
in order to control demand characteristics.
Strengths Limitations
High control over extraneous variables. Means any Can lack generalisability as lab environment may be
effect on the DV is likely to be manipulation of the IV. artificial and not like everyday life. Low external
Therefore, the researcher can be more certain about validity.
demonstrating cause and effect (high internal validity).
Participants are aware they are being tested and
Replication is more possible due to high level of may produce demand characteristics. Tasks
control. Replication is vital to check to see whether participants conduct are normally meaningless.
results are valid or just a ‘one off’.
Field experiments
A controlled experiment that’s carried out in a natural environment, usually the participants own
environment such as a school or workplace.
Researcher still manipulates IV but little control over extraneous variables
Participants are not always randomly allocated to the conditions of experiment. This means participant
variables aren’t necessarily controlled for.
participants may or may not know they’re taking part in the experiment as consent isn’t needed in a
public place, so behaviour may be more natural
Strengths Limitations
-Have higher mundane realism than lab -Loss of control of extraneous variables. Cause an
experiments as environment is more natural. effect between IV and DV more difficult to
May produce more valid or authentic behaviour. establish and precise replications may not be
-High external validity as participants are possible.
unaware, they are being studied. -Ethical issues arise – as participants are unaware
that they are being studied, they cannot consent
to being studied and this is an invasion of privacy.
, Natural
when researcher takes advantage of pre-existing variable.
Usually the participants everyday environment, it takes place when something happens that the researcher can
take advantage of.
IV is naturally occurring; it will vary even if the researcher isn’t interested in it
The effect the IV has on the DV can be observed
There’s no random allocation of participants.
Strengths Limitations
-Provide opportunities for research that may not Naturally occurring events happen rarely, reducing
have otherwise been undertaken for practical/ research opportunities. Also limits the ability to
ethical reasons. generalise findings.
Often have high external validity as they involve the Participants may not be randomly allocated to
study of real-life issues and problems as they arise, experimental conditions. This means that the
such as the effect of natural disaster on stress levels. researcher is less sure if IV affects DV.
Quasi
Often carried out under controlled conditions but also in the participants own environment
The IV is a condition that exists in participants and not something that varies
For example: gender, eye colour, disability
The researcher isn’t able to randomly allocate participants as the IV is a quality of the participant
Participants know they’re taking part in experiment
Strengths Limitations
Often carried out under controlled conditions Cannot randomly allocate participants to
and share strengths of lab experiments. conditions so there may be cofounding variables.
How to deal with practice and order effects?
Using technique counterbalancing – specifically called ABBA
What is an aim?
a general statement of what the researcher intends to investigate- purpose of the study.
‘to investigate…’
What is a Hypothesis?
a clear precise testable statement that states the relationships between the variables to be measured. Stated
at outset of the study. Can be directional or non-directional.
Directional hypothesis (one-tailed) – states the direction of the difference or the relationship.
o researchers use directional hypotheses when findings of previous research suggest a
particular outcome
o “People who … will be more…than those who...”
Non-Directional hypothesis (two-tailed)- states there is a difference between conditions but does not
specify the direction.
o Researchers use non-directional hypotheses when there is no previous research or findings
are contradictory
Null hypothesis
states there is no difference between conditions or co-variables.
Alternative hypothesis
states that there is a relationship between the two variables being studied
Directional alternative hypothesis(one tailed): specific about effect that IV will have on DV e.g. ‘girls
will score higher than boys in A level
Non-directional alternative hypothesis (two-tailed): Say IV will affect DV but not specific about how
this will be e.g. ‘a significant difference in A level scores of boys’ and girls’
Which one to pick? (directional or non-directional)
Directional = sufficient background evidence (previous research)
Non-directional = if evidence is unclear + researcher wants to suggest they are avoiding bias
,Types of variables
Independent variable - changes or is manipulated so the effect on the DV can be measured.
Dependent variable - measured by the researcher.
Extraneous variables
any variable, other than IV, that may influence the DV if it is not controlled.
these are identified at the beginning of an experiment to have their influence minimised.
Do not vary systematically.
Confounding variables
any variable, other than the IV, that may have affected the DV so we cannot be sure of the true
source of changes to the DV.
Vary systematically with the IV, e.g. personality.
Should have been controlled
Operationalised variables
clearly defining variables in terms of how they can be measured
Each variable should be operationalised in order to make the hypothesis clear and testable
Types of experimental method
Experimental method involves the manipulation of an IV to measure the effect on a DV.
Experiments may be laboratory, field, natural, or quasi.
Dependent on:
o How much control we have over IV
o How much control we have over extraneous variables
Experiment and variables
One variable kept constant
Another measured to see if it changes (IV) relative to the variable manipulated by experimenter (DV)
Establish a causal relationship between variables
,Lab experiments
Occurs in a controlled environment using standardised procedures and instructions that allows high
degree of control over extraneous variables e.g. skinners box
Controls variation of IV and measures change of DV
Participants can be randomly allocated to the conditions to control for participant variables. Material and
stimuli can also be randomly allocated
Participants are aware they are taking part in the experiment; however they may not know the true aims
in order to control demand characteristics.
Strengths Limitations
High control over extraneous variables. Means any Can lack generalisability as lab environment may be
effect on the DV is likely to be manipulation of the IV. artificial and not like everyday life. Low external
Therefore, the researcher can be more certain about validity.
demonstrating cause and effect (high internal validity).
Participants are aware they are being tested and
Replication is more possible due to high level of may produce demand characteristics. Tasks
control. Replication is vital to check to see whether participants conduct are normally meaningless.
results are valid or just a ‘one off’.
Field experiments
A controlled experiment that’s carried out in a natural environment, usually the participants own
environment such as a school or workplace.
Researcher still manipulates IV but little control over extraneous variables
Participants are not always randomly allocated to the conditions of experiment. This means participant
variables aren’t necessarily controlled for.
participants may or may not know they’re taking part in the experiment as consent isn’t needed in a
public place, so behaviour may be more natural
Strengths Limitations
-Have higher mundane realism than lab -Loss of control of extraneous variables. Cause an
experiments as environment is more natural. effect between IV and DV more difficult to
May produce more valid or authentic behaviour. establish and precise replications may not be
-High external validity as participants are possible.
unaware, they are being studied. -Ethical issues arise – as participants are unaware
that they are being studied, they cannot consent
to being studied and this is an invasion of privacy.
, Natural
when researcher takes advantage of pre-existing variable.
Usually the participants everyday environment, it takes place when something happens that the researcher can
take advantage of.
IV is naturally occurring; it will vary even if the researcher isn’t interested in it
The effect the IV has on the DV can be observed
There’s no random allocation of participants.
Strengths Limitations
-Provide opportunities for research that may not Naturally occurring events happen rarely, reducing
have otherwise been undertaken for practical/ research opportunities. Also limits the ability to
ethical reasons. generalise findings.
Often have high external validity as they involve the Participants may not be randomly allocated to
study of real-life issues and problems as they arise, experimental conditions. This means that the
such as the effect of natural disaster on stress levels. researcher is less sure if IV affects DV.
Quasi
Often carried out under controlled conditions but also in the participants own environment
The IV is a condition that exists in participants and not something that varies
For example: gender, eye colour, disability
The researcher isn’t able to randomly allocate participants as the IV is a quality of the participant
Participants know they’re taking part in experiment
Strengths Limitations
Often carried out under controlled conditions Cannot randomly allocate participants to
and share strengths of lab experiments. conditions so there may be cofounding variables.
How to deal with practice and order effects?
Using technique counterbalancing – specifically called ABBA
