Exam 2 Flashcards
What is a variable?
Something that varies and must have at least two levels.
What is a constant?
Something that could potentially vary but that has only one level in the study in question.
What is a measured variable?
One whose levels are simply observed and recorded.
What is a manipulated variable?
A variable that a researcher controls.
What is a construct?
Also known as conceptual variable; an abstract concept such as “shyness” or “intelligence”.
What is a conceptual definition?
The theoretical definition of a construct or conceptual variable.
What is to operationalize?
To turn a concept of interest into a measured or manipulated variable.
What are the three types of claims?
Frequency claims, association claims and causal claims.
What is a frequency claim?
A particular rate or degree of a single variable. Example: “1 in 25 teens attempt suicide”.
What is an association claim?
Argues that one level of a variable is likely to be associated with a particular level of another variable.
What is a correlation?
When one variable changes, the other variable tends to change too.
What is a positive correlation?
As one variable increases, the other increases as well.
What is a negative correlation?
As one variable increases, the other decreases.
What is a zero correlation?
No link between variables.
What is a causal claim?
Argues that one of the variables is responsible for changing the other.
What are the three criteria for making a causal claim?
The two variables are correlated (covariance); the causal variable came first (temporal precedence); no other explanation exists for the relationship (internal validity).
What is validity?
The appropriateness of a conclusion or decision.
What are the four types of validity?
Construct validity, external validity, statistical validity, internal validity.
What is construct validity?
How well the variables in a study are measured or manipulated.
What is external validity?
The extent to which the results of a study generalize to a larger population or to other situations.
What is statistical validity?
The strength of an effect and its statistical significance.
What is internal validity?
The extend to which the manipulated variable is responsible for the effect on the measured variable, rather than some other variable. Applies to causal claims only.
What is a Type I error?
Mistaken conclusion that there is an association between two variables when there really is none. Also known as “false positive”.
What is a Type II error?
Mistaken conclusion that there is no association between two variables when there really is one. Also known as “false negative” or “miss”.
What is covariance?
Variable A changes as variable B changes. Correlation.
What is temporal precedence?
Variable A comes first in time, before B.
What is an independent variable?
The manipulated variable.
What is a dependent variable?
The measured variable.
What are the three types of measures?
Self-reported, observational, physiological.
What is a self-report measure?
Operationalization by recording people’s answers to questions about themselves.
What is an observational measure?
Operationalization by recording observable behaviour or physical traces of behaviour.
What is a physiological measure?
Operationalization by recording biological data.
What is a categorical variable?
Levels as categories.
What is a quantitative variable?
Levels as meaningful numbers.
What are the three types of quantitative variables?
Ordinal scale, interval scale, ratio scale.
What is an ordinal scale?
Numerals represent a rank order.
What is an interval scale?
Subsequent numerals present equal distances, without true zero.
What is a ratio scale?
Numerals represent equal distances with a true zero.
What is reliability?
How consistent the results of a measure are.
What is validity?
Whether the operationalization measures what it is supposed to measure.
What are the three types of reliability?
Test-retest, interrater, internal.
What is test-retest reliability?
When people take a test twice, the scores should be consistent.
What is interrater reliability?
When two or more independent observers come up with consistent findings.
What is internal reliability?
Questions intended to measure a similar construct return similar results.
What are the five ways to assess construct validity?
Subjective: face validity, content validity. Empirical: Criterion, convergent, discriminant.
What is face validity?
It looks like what you want to measure.
What is content validity?
The measure contains all the parts that your theory says it should contain.
What is criterion validity?
Your measure is correlated with a relevant outcome.
What is convergent validity?
Your measure is more strongly associated with measures of similar constructs.
What is discriminant validity?
Your measure is less strongly associated with measures of dissimilar constructs.
Explain the relationship between reliability and validity.
A measure may be less valid than it is reliable, but it cannot be more valid than it is reliable. Reliability is necessary, but not sufficient, for validity.
What are the nine internal validity threats?
Maturation, history, regression towards the mean, attrition, testing effect, instrumentation, observer bias, demand characteristics, placebo effect.
What is a maturation threat?
A change in behaviour that emerges more or less spontaneously over time. Particularly relevant in developmental research.
What is a history threat?
Historical or external event that affects most members of a group at the same time.
What is a regression threat?
When a performance is extreme at time 1, measure at time 2 is likely to be less extreme.
What is an attrition threat?
Reduction in participant numbers that occurs when people drop out of the study before the end. Problematic when attrition is systematic, i.e. when only a certain kind of participant drops out.
What is a testing effect threat?
A change in the participants as a result of taking a test more than once.
What is an instrumentation threat?
When measuring instruments change over time or is bad for measuring a construct.
How do you prevent a maturation threat?
By using a control group.
How do you prevent a history threat?
By using a control group.
How do you prevent a regression threat?
By using a control group and examining results.
How do you prevent an attrition threat?
By providing incentives, by removing the scores of those who dropped out.
How do you prevent a testing effect threat?
By abandoning pretest, by using two different forms of the same test.
How do you prevent an instrumentation threat?
By using posttest-only design, by training observers, by counterbalancing, by calibrating instruments.
What is observer bias?
Occurs when researchers’ expectations influence their interpretation of the results.
How do you prevent observer bias?
Control group, single-blind and double-blind studies.
What is a demand characteristic threat?
When participants guess what the study is about and change their behaviour accordingly.
How do you prevent demand characteristics?
Control group, single-blind and double-blind studies.
What is the placebo effect?
When people receive a treatment and really improve–but only because the recipients believe they are receiving a valid treatment.
How do you prevent the placebo effect?
You can’t–it’s real. But you can control for it via a double-blind placebo control study.
