variables

• a test is valid when it measures what it claims to be measuring
• a test lacks validity if it does not measure what it claims to be measuring or is affected by confounding or extraneous variables
• we can assess the validity of a test using face validity or concurrent validity
• face validity is when the test is presented in a way that looks like it is measuring what it is supposed to measure
• we can asses concurrent validity by assessing the results obtained in one test against the results obtained in another test that we know is valid
• reliability is a test of consistency
• a test has external reliability if the results are consistent everytime the study is repeated
• external reliability can be tested using the test-retest method which involves administering the test to the same participants on two different occasions
• a test has internal reliability if the individual questions on a test are consistent with each other
• internal reliability can be tested using the split-half method which involves splitting the test into two and seeing if the results on the two halves of the test are consistent with each other
• 3 types of extraneous variables: participant variables, investigator effects, situational variables
• participant variables are personal characteristics of the participant
• investigator effects are when the researcher influences the behaviour of the participants
• situational variables are features of the external environment that can affect the results of a study
• demand characteristics are when investigator effects or situational variables act as hints that enable participants to guess the aim of the study
• uncontrolled extraneous variables reduce the validity and reliability of the study
• investigator effects and situational variables can be controlled using standardisation
• standardisation is when researchers make an extraneous variable the same for all participants in the study
• participant variables can be solved with matching and random allocation
• matching is when a particular characteristic of the participants is divided equally across groups
• random allocation is when participants are randomly assigned to the experimental and control groups
• we can control demand characteristics through blinding
• a single blind procedure is when the participant is not aware of the research aims and/or of which condition of the experiment they are in
• double blind procedures are when neither the participant nor the researcher conducting the study are aware of the aims of the research or what group the participant is in
• internal validity is when the study measures what it claims to measure and extraneous variables are controlled
• external validity is when the results of the study generalise to other people and situations
• the 3 types of external validity are ecological validity, temporal validity and population validity
• ecological validity is when the results of a study generalise to how people act in every day life
• temporal validity is when the results of a study generalise over time
• population validity is when the results of a study generalise to other populations