Research methods revision
What is a science
The scientific method
The scientific method (also known as scientific/experimental method) is the steps
scientists follow when conducting evidence to test cause and effect relationships
1. Aims
➔ Once a question has been found it is turned into a statement called an aim
➔ It always tells us the reason for carrying out the experiment
➔ Always starts with “to”
2. Hypothesis
➔ A prediction about the experiment is the hypothesis
➔ A hypothesis is not always needed
3. Methods
➔ The exact procedure that the researcher follows
4. Results
➔ The changes observed during the experiment
5. Conclusions
➔ The interpretation of the results
Independent and dependent variables
An independent variable is the thing we change
A dependent variable is the thing we measure
Levels on independent variables
In every experiment there will be at least two variables of the IV so they know that any
change in the measure (DV) will be because of the change in the IV
- These different versions of the IV are called the levels of independent variables
Operationalisation
Operlisaionalising variables means defining how the variables is going to be measured
Features of science
,Features of science
The key features of science:
1. Hypothesis testing
➔ We test the hypothesis by using the scientific process
➔ If the hypothesis testing leads to results that don't support the hypothesis,
then the hypothesis needs to be adjusted
2. Empirical evidence
➔ When information is collected through direct observation its called empirical
evidence
➔ Science involves testing hypotheses through empirical evidence
3. Falsifiability
➔ When it is possible for a hypothesis to be proven false, the hypothesis is
falsifiable
➔ To test a hypothesis it must be possible to prove it wrong
➔ If a hypothesis is not falsifiable then it isn't scientific
4. Replicability
➔ To make sure the results aren't just a coincidence, scientists need to retest
their theory and see whether they can get the same results again. This
means they are replicating the study
➔ If the results of the study are the same, the results are replicated
5. Control
➔ Science involves comparing an experimental group to a control group
➔ A control group is a level of the IV which is not manipulated by the
researcher
➔ An experimental group is the level of the IV where the researcher does
manipulate the IV
➔ Extraneous variables are something other than the IV which can affect the
DV. Researchers need to control the EVs
★ When an extraneous variable varies according to the level of the IV,
it's called a confounding variable
6. Objectivity
➔ When a researcher lets their personal views (personal bias) affect their
research they lack objectivity
➔ Researchers should try to be as objective as possible
7. Theory construction
➔ A theory must be a comprehensive explanation that has already been
backed up by the scientific method
➔ This theory should be able to be used to test predictions about the world.
The theory must be falsifiable
,Issues in psychological research
Validity
When a test measures what it claims to measure, it is valid but when it doesn't it lacks
validity
- For the results of a stay to be valid, the results shouldnt be affected by any
extraneous variables or confounding variables
Assessing validity
Face validity:
- Face validity is where a researcher looks at the test and sees if it is a good measure
of what they want to study
- However, sometimes the appearance is deceiving so other methods of assessing
validity needs to be used
Concurrent validity:
- When a test produces similar results to the other test that measures the same
behaviours which is known to be valid, it has concurrent validity
- We compare the results of the tests to see if there is concurrent validity
Reliability
When the results of a study are consistent every time the study is repeated, the study is
reliable
- One reason why a study can lack reliability is if there are extraneous variables that
affect the measurement
- Another reason why a study can lack reliability is if the questionnaire or test used
to measure the DV is unreliable itself
External reliability
External reliability is when the results of a study are consistent every time the study is
repeated
Internal reliability
Internal reliability is how consistent the individual items on a test or questionnaire are with
each other
, - If a questionnaire’s individual answers give the same results then the questionnaire
has high internal reliability. But if it gives different results it has low internal
reliability
Split half method
To see if a test has good internal reliability, the split half method can be used
- Once a participant fills in a questionnaire the researcher splits it in two halfs, A and
B then calculates the score in part A and then the same thing for part B
- If both halfs give a similar result then it has high internal reliability
- If both halfs give a different result then it is not internally reliability
Test-retest method
To see if the test or method is externally reliable the test-retest method can be used
- This is where the test is done multiple times on different occasions and results are
compared
- If the results are similar they are consistent and the questionnaire is externally
reliable
Extraneous variables
Participant variables
Participant variables are extraneous variables that are personal characteristics of the
participant that could influence their behaviour
Investigator effects
Investigator effects are extraneous variables where a researcher influences the
participants behaviour and therefore the results of the study
- Also called experimenter variables
Researcher expectations
Researchers expectations can influence the behaviour of the researcher and therefore
affect the behaviour of the participants
- This is an example of investigator effects
Situational variables
What is a science
The scientific method
The scientific method (also known as scientific/experimental method) is the steps
scientists follow when conducting evidence to test cause and effect relationships
1. Aims
➔ Once a question has been found it is turned into a statement called an aim
➔ It always tells us the reason for carrying out the experiment
➔ Always starts with “to”
2. Hypothesis
➔ A prediction about the experiment is the hypothesis
➔ A hypothesis is not always needed
3. Methods
➔ The exact procedure that the researcher follows
4. Results
➔ The changes observed during the experiment
5. Conclusions
➔ The interpretation of the results
Independent and dependent variables
An independent variable is the thing we change
A dependent variable is the thing we measure
Levels on independent variables
In every experiment there will be at least two variables of the IV so they know that any
change in the measure (DV) will be because of the change in the IV
- These different versions of the IV are called the levels of independent variables
Operationalisation
Operlisaionalising variables means defining how the variables is going to be measured
Features of science
,Features of science
The key features of science:
1. Hypothesis testing
➔ We test the hypothesis by using the scientific process
➔ If the hypothesis testing leads to results that don't support the hypothesis,
then the hypothesis needs to be adjusted
2. Empirical evidence
➔ When information is collected through direct observation its called empirical
evidence
➔ Science involves testing hypotheses through empirical evidence
3. Falsifiability
➔ When it is possible for a hypothesis to be proven false, the hypothesis is
falsifiable
➔ To test a hypothesis it must be possible to prove it wrong
➔ If a hypothesis is not falsifiable then it isn't scientific
4. Replicability
➔ To make sure the results aren't just a coincidence, scientists need to retest
their theory and see whether they can get the same results again. This
means they are replicating the study
➔ If the results of the study are the same, the results are replicated
5. Control
➔ Science involves comparing an experimental group to a control group
➔ A control group is a level of the IV which is not manipulated by the
researcher
➔ An experimental group is the level of the IV where the researcher does
manipulate the IV
➔ Extraneous variables are something other than the IV which can affect the
DV. Researchers need to control the EVs
★ When an extraneous variable varies according to the level of the IV,
it's called a confounding variable
6. Objectivity
➔ When a researcher lets their personal views (personal bias) affect their
research they lack objectivity
➔ Researchers should try to be as objective as possible
7. Theory construction
➔ A theory must be a comprehensive explanation that has already been
backed up by the scientific method
➔ This theory should be able to be used to test predictions about the world.
The theory must be falsifiable
,Issues in psychological research
Validity
When a test measures what it claims to measure, it is valid but when it doesn't it lacks
validity
- For the results of a stay to be valid, the results shouldnt be affected by any
extraneous variables or confounding variables
Assessing validity
Face validity:
- Face validity is where a researcher looks at the test and sees if it is a good measure
of what they want to study
- However, sometimes the appearance is deceiving so other methods of assessing
validity needs to be used
Concurrent validity:
- When a test produces similar results to the other test that measures the same
behaviours which is known to be valid, it has concurrent validity
- We compare the results of the tests to see if there is concurrent validity
Reliability
When the results of a study are consistent every time the study is repeated, the study is
reliable
- One reason why a study can lack reliability is if there are extraneous variables that
affect the measurement
- Another reason why a study can lack reliability is if the questionnaire or test used
to measure the DV is unreliable itself
External reliability
External reliability is when the results of a study are consistent every time the study is
repeated
Internal reliability
Internal reliability is how consistent the individual items on a test or questionnaire are with
each other
, - If a questionnaire’s individual answers give the same results then the questionnaire
has high internal reliability. But if it gives different results it has low internal
reliability
Split half method
To see if a test has good internal reliability, the split half method can be used
- Once a participant fills in a questionnaire the researcher splits it in two halfs, A and
B then calculates the score in part A and then the same thing for part B
- If both halfs give a similar result then it has high internal reliability
- If both halfs give a different result then it is not internally reliability
Test-retest method
To see if the test or method is externally reliable the test-retest method can be used
- This is where the test is done multiple times on different occasions and results are
compared
- If the results are similar they are consistent and the questionnaire is externally
reliable
Extraneous variables
Participant variables
Participant variables are extraneous variables that are personal characteristics of the
participant that could influence their behaviour
Investigator effects
Investigator effects are extraneous variables where a researcher influences the
participants behaviour and therefore the results of the study
- Also called experimenter variables
Researcher expectations
Researchers expectations can influence the behaviour of the researcher and therefore
affect the behaviour of the participants
- This is an example of investigator effects
Situational variables
