Chapter 3: Three Claims & Four Validities

Frequency claims

describe a particular rate or degree of a single variable (eg. percentage of a variable, # of people who engage in an activity)

Association claims

a claim about two variables, in which the value (level) of one variable is said to be associated with a particular level of another variable

Casual claims

argues that one of the variables is responsible for changing the other, two variables covary (tentative language)

Positive association

an association in which high levels of one variable go with high levels of the other variable, and vice versa

Negative association or inverse association

an association in which high levels of one variable go with low levels of the other variable, and vice versa

Zero association

no association between variables (no slope)

Correlative/covary

that when one variable changes the other variable tends to change too

Correlational study

a research project designed to discover the degree to which two variables are related to each other (relationship)

Temporal precedence

one of three criteria for establishing a causal claim, stating that the proposed causal variable comes first in time, before the proposed outcome variable

Construct validity

the extent to which variables measure what they are supposed to measure, how well it is operationalized

Internal validity

extent to which we can draw cause-and-effect inferences from a study

Covariance

A measure of linear association between two variables. Positive values indicate a positive relationship; negative values indicate a negative relationship

External validity

extent to which we can generalize findings to real-world settings, beyond the original study

Statistical validity

the extent to which statistical conclusions derived from a study are precise, reasonable, and replicable

Internal validity

extent to which we can draw cause-and-effect inferences from a study, a third variable criterion refers to a study ability to eliminate alternative explanations for the association

Variable

something that varies must have at least two levels (values)

Constant

something that could potentially vary, only has one level in the study

Measured variable

one whose levels are simply observed and recorded (dependent variable)

Manipulated variable

one that a researcher controls, usually by assigning study participants to different levels of that variable (independent variable)

Conceptual variable

abstract names used when researchers are discussing theories

Operational defintion or operational variables

used when testing hypotheses with empirical research

Claim

an argument someone is trying to make, researchers make claims about theories based on data

Validity

the appropriateness of a conclusion or decision, a valid claim is reasonable, accurate and justifiable

Generalizability

the extent to which we can claim our findings inform us about a group larger than the one studied

Confidence interval or margin error of the estimate

a range designed to include the true population value a high proportion of the time

Independent variable

variable that is manipulated, done by assigning participants to be at one level or another

Dependent variable

variable that is measured

Random assignment

used to ensure validity of all groups, making sure they are as similar as possible