Psychology - Research Methods - Reliability, Validity and Extraneous Variables Flashcards
Reliability
Refers to the consistency of a research study especially when it is repeated again and the results are the same
What are the two types of reliability?
external and internal
External reliability
Whether a test and the results gained are consistent over time. Can use test-retest
test-retest method
can be used to assess external validity. A research study is conducted once, and then it is conducted again in the future. If the results gained from the both tests are similar then the study can be said to be reliable.
internal reliability
Whether a test and the results gained are consistent within itself. Can use split half technique
What does the Split half technique assess?
assesses the internal reliability of questionnaires.
What is the split half technique?
The questionnaire is split in half and if participants score similarly on both halves of the questionnaire then the questions are measuring the same factors and the questionnaire has internal reliability.
Validity
Validity means that a study is measuring what it intends to measure when referring to the aim of the study.
How many types of validity are there?
four
what are the types of validity?
External, Participant, Temporal, Internal
External validity
This is the extent to which the findings of a study can be generalised to other settings.
Participant validity
The results from the participants used in the study can be generalised to the target population
Temporal validity
The results from the study can be generalised to people in today’s contemporary society
Internal validity
This is when the outcome of the study is a direct result of the manipulation of the independent variable (IV) upon the dependent variable (DV) and has not been affected by extraneous variables (EV).
What are the three categories of extraneous variables
Participant variables, Situational variables, Experimenter variables
participant variables
characteristics of the participants which may affect the DV (e.g. intelligence, age, gender, personality etc.)
What can help avoid participant variables
Matched pairs and repeated measures design
Situational variables
factors in the environment where the experiment is conducted that could affect the dependent variable (e.g. temperature, time of day, lighting, noise etc.).
How would you resolve situational variables?
standardisation
Standardisation
making sure that all the conditions, materials, and instructions are the same for all participants
Experimenter variables
factors to do with the experimenter which can affect the dependent variable, for example personality, appearance, and conduct of the experimenter
Standardised instructions
should ensure that the experimenter acts in a similar way with all participants and follows a script and speaks to everyone in the same manner and tone.
Investigator effects
Investigators may inadvertently influence the results of their research
how could you overcome investigator effects
double blind technique
double-blind technique
when neither the participants nor the investigator knows the aim of the study and hopefully this will mean the data collected will be more valid.
how would you overcome demand characteristics?
single blind technique
Single blind technique
This involves making sure participants do not know what the aim of the study is so that hopefully this will not influence their behaviour unduly
