Final Exam

Evidence-based Treatment

A psychotherapy technique whose effectiveness has been supported by empirical research. (page 8)

Empiricism

The use of verifiable evidence as the basis for conclusions; collecting data systematically and using it to develop, support, or challenge a theory. Also called empirical methodor empirical research. (page 10)

Theory

A statement or set of statements that describes general principles about how variables relate to one another. (page 13)

Hypothesis

A statement of the specific result the researcher expects to observe from a particular study, if the theory is accurate. Also called prediction. (page 13)

Data (Plural; Singular Datum)

A set of observations representing the values of some variable, collected from one or more research studies. (page 13)

Falsifiability

A feature of a scientific theory, in which it is possible to collect data that will indicate that the theory is wrong. (page 14)

Parsimony

The degree to which a theory provides the simplest explanation of some phenomenon. In the context of investigating a claim, the simplest explanation of a pattern of data; the best explanation that requires making the fewest exceptions or qualifications. (page 15)

Weight of Evidence

A conclusion drawn from reviewing scientific literature and considering the proportion of studies that is consistent with a theory. (page 15)

Applied Research

Research whose goal is to find a solution to a particular real-world problem. See also basic research, translational research. (page 16)

Basic Research

Research whose goal is to enhance the general body of knowledge, without regard for direct application to practical problems. See also applied research, translational research. (page 16)

Translational Research

Research that uses knowledge derived from basic research to develop and test solutions to real-world problems. See also applied research, basic research. (page 16)

Journal

A monthly or quarterly periodical containing peer-reviewed articles on a specific academic discipline or subdiscipline, written for a scholarly audience. (page 17)

Journalism

News and commentary published or broadcast in the popular media and produced for a general audience. (page 18)

Comparison

A group in an experiment whose levels on the independent variable differ from those of the treatment group in some intended and meaningful way. Also called comparison condition. (page 26)

cofound

A general term for a potential alternative explanation for a research finding; a threat to internal validity. (page 29)

Confederate

An actor who is directed by the researcher to play a specific role in a research study. (page 29)

Probabilistic

Describing the empirical method, stating that science is intended to explain a certain proportion (but not necessarily all) of the possible cases. (page 31)

Availability heuristic

A bias in intuition, in which people incorrectly estimate the frequency of something, relying predominantly on instances that easily come to mind rather than using all possible evidence in evaluating a conclusion. (page 33)

present/present bias

A bias in intuition, in which people incorrectly estimate the relationship between an event and its outcome, focusing on times the event and outcome are present, while failing to consider evidence that is absent and harder to notice. (page 35)

Confirmation bias

The tendency to consider only the evidence that supports a hypothesis, including asking only the questions that will lead to the expected answer. (page 36)

Bias blind spot

The tendency for people to think that compared to others, they themselves are less likely to engage in biased reasoning. (page 37)

empirical journal article

A scholarly article that reports for the first time the results of a research study. (page 42)

review journal article

An article summarizing all the studies that have been published in one research area. (page 42)

meta-analysis

A way of mathematically averaging the effect sizes of all the studies that have tested the same variables to see what conclusion that whole body of evidence supports. (page 42)

effect size

The magnitude, or strength, of a relationship between two or more variables. (page 44)

Variable

An attribute that varies, having at least two levels, or values. See also dependent variable, independent variable, manipulated variable, measured variable. (page 58)

level

One of the possible variations, or values, of a variable. Also called condition. (page 58)

constant

An attribute that could potentially vary but that has only one level in the study in question. (page 58)

measured variable

A variable in a study whose levels (values) are observed and recorded. See also manipulated variable. (page 58)

manipulated variable

A variable in an experiment that a researcher controls, such as by assigning participants to its different levels (values). See also measured variable. (page 58)

conceptual variable

A variable of interest, stated at an abstract, or conversational, level. Also called construct. See also conceptual definition. (page 59)

construct

A variable of interest, stated at an abstract level, usually defined as part of a formal statement of a psychological theory. See also conceptual variable. (page 59)

conceptual definition

A researcher's definition of a variable at the theoretical level. Also called construct. See also conceptual variable. (page 59)

operational definition

The specific way in which a concept of interest is measured or manipulated as a variable in a study. Also called operationalization or operational variable. (page 59)

operational variable

The specific way in which a concept of interest is measured or manipulated as a variable in a study. Also called operationalization or operational definition. (page 59)

operationalize

To turn a conceptual definition of a variable into a specific measured variable or manipulated variable in order to conduct a research study. (page 59)

claim

The argument a journalist, researcher, or scientist is trying to make. (page 61)

frequency claim

A claim that describes a particular rate or degree of a single variable. (page 62)

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. (page 63)

correlate

To occur or vary together (covary) systematically, as in the case of two variables. See also correlational study, covariance. (page 63)

correlational study

A study that includes two or more variables, in which all of the variables are measured; can support an association claim. (page 64)

positive association

An association in which high levels of one variable go with high levels of the other variable, and low levels of one variable go with low levels of the other variable. Also called positive correlation. See also curvilinear association, negative association, zero association. (page 64)

scatterplot

A graphical representation of an association, in which each dot represents one participant in the study measured on two variables. (page 64)

negative association

An association in which high levels of one variable go with low levels of the other variable, and vice versa. Also called inverse association, negative correlation. See also curvilinear association, positive association, zero association. (page 64)

zero association

A lack of systematic association between two variables. Also called zero correlation. See also curvilinear association, positive association, negative association. (page 64)

causal claim

A claim arguing that a specific change in one variable is responsible for influencing the value of another variable. (page 66)

validity

The appropriateness of a conclusion or decision. See also construct validity, external validity, internal validity, statistical validity. (page 69)

construct validity

An indication of how well a variable was measured or manipulated in a study. (page 69)

generazalizability

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 or contexts. (page 70)

external validity

An indication of how well the results of a study generalize to, or represent, individuals or contexts besides those in the study itself. See also generalizability. (page 70)

statistical validity

the extent to which statistical conclusions derived from a study are accurate and reasonable. Also called statistical conclusion validity. (page 70)

margin of error of the estimate

A statistic, based in part on sample size, indicating the probable true value of a percentage estimate in the population. (page 70)

type I error

A "false positive" result in the statistical inference process, in which researchers conclude that there is an effect in a population, when there really is none. (page 72)

type II error

A "miss" in the statistical inference process, in which researchers conclude that their study has not detected an effect in a population, when there really is one. (page 73)

covariance

The degree to which two variables go together. Also one of 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. See also internal validity, temporal precedence. (page 74)

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. See also covariance, internal validity. (page 74)

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. Also called third-variable criterion. See also covariance, temporal precedence. (page 74)

experiment

A study in which one variable is manipulated and the other is measured. (page 75)

independent variable

In an experiment, a variable that is manipulated. In a multiple-regression analysis, a predictor variable used to explain variance in the criterion variable. See also dependent variable. (page 75)

dependent variable

In an experiment, the variable that is measured. In a multiple-regression analysis, the single outcome, or criterion variable, the researchers are most interested in understanding or predicting. Also called outcome variable. See also independent variable. (page 75)

random assignment

The use of a random method (e.g., flipping a coin) to assign participants into different experimental groups. (page 76)

principle of beneficence

An ethical principle from the Belmont Report stating that researchers must take precautions to protect participants from harm and to promote their well-being. See also principle of justice, principle of respect for persons. (page 95)

principle of justice

An ethical principle from the Belmont Report calling for a fair balance between the kinds of people who participate in research and the kinds of people who benefit from it. See also principle of beneficence, principle of respect for persons. (page 96)

observational measure

A method of measuring a variable by recording observable behaviors or physical traces of behaviors. Also called behavioral measure. (page 121)

quantitative variable

A variable whose values can be recorded as meaningful numbers. (page 123)

ordinal scale

A quantitative measurement scale whose levels represent a ranked order, and in which distances between levels are not equal (e.g., order of finishers in a race).

interval scale

A quantitative measurement scale that has no "true zero," and in which the numerals represent equal intervals (distances) between levels (e.g., temperature in degrees).

ratio scale

A quantitative measurement scale in which the numerals have equal intervals and the value of zero truly means "none" of the variable being measured.

reliability

The consistency of the results of a measure

validity

The appropriateness of a conclusion or decision

interrater reliability

The degree to which two or more coders or observers give consistent ratings of a set of targets

internal reliability

In a measure that contains several items, the consistency in a pattern of answers, no matter how a question is phrased.

Cronbach’s Alpha

A correlation-based statistic that measures a scale's internal reliability. Also called coefficient alpha.

face validity

The extent to which a measure is subjectively considered a plausible operationalization of the conceptual variable in question.

Content Validty

The extent to which a measure captures all parts of a defined construct.

Criterion Validity

An empirical form of measurement validity that establishes the extent to which a measure is associated with a behavioral outcome with which it should be associated.

known-groups paradigm

A method for establishing criterion validity, in which a researcher tests two or more groups who are known to differ on the variable of interest, to ensure that they score differently on a measure of that variable.

convergent validity

An empirical test of the extent to which a self-report measure correlates with other measures of a theoretically similar construct.

discriminant validity

An empirical test of the extent to which a self-report measure does not correlate strongly with measures of theoretically dissimilar constructs. Also called divergent validity.

double-barreled question

A type of question in a survey or poll that is problematic because it asks two questions in one, thereby weakening its construct validity.

negatively worded question

A question in a survey or poll that contains negatively phrased statements, making its wording complicated or confusing and potentially weakening its construct validity.

bivariate correlation

An association that involves exactly two variables. Also called bivariate association.

statistical significance

A researcher's assessment of whether a result from a sample (such as an association or a difference between groups) could have come from a population in which there is no association or no difference. When the sample's result is extreme, it would rarely be found in such a population and is said to be statistically significant

curvilinear association

An association between two variables which is not a straight line; instead, as one variable increases, the level of the other variable increases and then decreases (or vice versa).

directionality problem

In a correlational study, the occurrence of both variables being measured around the same time, making it unclear which variable in the association came first.

third-variable problem

In a correlational study, the existence of a plausible alternative explanation for the association between two variables

spurious association

A bivariate association that is attributable only to systematic mean differences on subgroups within the sample; the original association is not present within the subgroups.

multivariate design

A study designed to test an association involving more than two measured variables

autocorrelation

In a longitudinal design, the correlation of one variable with itself, measured at two different times.

cross-lag correlation

In a longitudinal design, a correlation between an earlier measure of one variable and a later measure of another variable.

multiple regression

A statistical technique that computes the relationship between a predictor variable and a criterion variable, controlling for other predictor variables. Also called multivariate regression.

control for

Holding a potential third variable at a constant level (statistically or experimentally) while investigating the association between two other variables.

criterion variable

The variable in a multiple-regression analysis that the researchers are most interested in understanding or predicting. Also called dependent variable

predictor variable

A variable in multiple-regression analysis that is used to explain variance in the criterion variable. Also called independent variable.

comparison group

A group in an experiment whose levels on the independent variable differ from those of the treatment group in some intended and meaningful way. Also called comparison condition.

design confound

A threat to internal validity in an experiment in which a second variable happens to vary systematically along with the independent variable and therefore is an alternative explanation for the results.

systematic variability

In an experiment, a description of when the levels of a variable coincide in some predictable way with experimental group membership, creating a potential confound.

unsystematic variability

In an experiment, a description of when the levels of a variable fluctuate independently of experimental group membership, contributing to variability within groups.

selection effect

A threat to internal validity that occurs in an independent-groups design when the kinds of participants at one level of the independent variable are systematically different from those at the other level.

concurrent-measures design

An experiment using a within-groups design in which participants are exposed to all the levels of an independent variable at roughly the same time, and a single attitudinal or behavioral preference is the dependent variable