Chp. 3 Verms - 3 Claims, 4 Validities: Interrogation Tools for Consumers of Research

variable

an attribute that varies, having at least two levels, or values

level (also condition)

one of the possible variations, or values, of a varaible

constant

an attribute that could potentially vary but that has only one level in the study in question

measured variable

a variable in a study whose levels (values) are observed and recorded

manipulated variable

a variable in an experiment that a researcher controls, such as by assigning participants to its different levels (values)

construct

a variable of interest, stated at an abstract level, usually defined as part of a formal statement of a psychological theory

conceptual variable

a variable of interest, stated at an abstract, or conversational, level

operational definition (also operationalization, operational variable)

the specific way in which a concept of interest is measured/manipulated as a variable in a study

operationalize

to turn a conceptual definition of a variable into a specific measured variable or manipulated variable in order to conduct a research study

claim

the argument a journalist, researcher, or scientist is trying to make

frequency claim

a claim that describes a particular rate/degree of a single variable

association claim

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

correlate

to occur or vary together (covery) systematically, as in the case of two variables

correlational study

a study that includes two or more variables, in which all of the variables are measured; can support an association claim

positive association

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

scatterplot

a graphical representation of an association, in which each dot represents one participant in the study measured on two variables

negative association

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

zero association

a lack of systematic association between two variables

causal claim

a claim arguing that a specific change in one variable is responsible for influencing the value of another variable

validity

the appropriateness of a conclusion/decision

construct validity

an indication of how well a variable was measured/manipulated in a study

generalizability

the extent to which the subjects in a study represent the populations they are intended to represent; how well the settings in a study represent other settings/contexts

external validity

an indication of how well the results of a study generalize to, or represent, individuals/contexts besides those in the study itself

statistical validity

the extent to which statistical conclusions derived from a study are accurate and reasonable

point estimate

a single estimate of some population value (such as a percentage, correlation, or difference) based on data from a sample

confidence interval

a given range indicated by a lower and upper value that is designed to capture that population value for some point estimate; a high proportion of CIs will capture the true population value

margin of error of the estimate

in the context of a percentage estimate, an inferential statistic providing a range of values that has a high probability of containing the true population value

covariance

the degree to which two variables go together; also one of the three criteria for establishing a causal claim, which states that, in a study’s results, the proposed causal variable must vary systematically with changes in the proposed outcome variable

temporal precedence

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

internal validity

one of three criteria for establishing a causal claim; a study’s ability to rule out alternative explanations for a causal relationship between two variables

experiment

a study in which at least one variable is manipulated and another is measured

independent variable

in an experiment, a variable that is manipulated

dependent variable

in an experiment, the variable that is measured

random assignment

the use of a random method to assignment participants into different experimental groups