are hypothetical attributes or mechanisms that help explain and predict behavior in theory

is a procedure for indirectly measuring and defining a variable that cannot be observed or measured directly. specifies a measurement procedure.

the degree to which the measurement process measures the variable that it claims to measure

an unscientific form of validity demonstrated when a measurement procedure superficially appears to measure what it claims to measure

when scores obtained from a new measure are directly related to scores obtained from an established measure of the same variable

demonstrated when scores obtained from a measure accurately predict behavior according to a theory

requires that the scores obtained from a measurement procedure behave exactly the same as the variable itself

demonstrated by a strong relationship between the scores obtained from two or more different methods of measuring the same construct

demonstrated by showing little or no relationship between the measurements of two different constructs

is the stability or consistency of the measurement

Common Sources of Error

is established by comparing the scores obtained from two successive measurements of the same individual and calculating a correlation between the two sets of scores

is the degree of agreement between two observers who simultaneously record measurements of the behavior

is obtained by splitting the items on a questionnaire or test in half, computing a sperate score for each half, and then calculating the degree of consistency between the two scores for a group of participants

simply represent qualitative differences in the variable measured. Have different names but are not related to each other in any systematic way.

have different names and are organized sequentially. Consists of a series of ranks.

most direct way to assess a construct. participant answers questions about themselves. A disadvantage is that participants can lie.

involve brain imaging techniques such as PET scans and MRIs. researchers monitor activity levels in specific areas of the brain during different kinds of activity.

The lack of agreement between two measures and confuses interpretation of results

the clustering of scores at the high end of a measurement scale, allowing little or no possibility of increases in value

the clustering of scores at the low end of a measurement scale, allowing little or no possibility of decreases in value

occurs when the measurements obtained in a study are influenced by the experimenter's expectation or personal beliefs regarding the outcome of the study

if the researcher does not know the predicted outcome

if both the researcher and the participants are unaware of the predicted outcome

refers to any of the potential cues or features of a study that suggest to the participants what the purpose and hypothesis is, and influence the participants to respond or behave in a certain way

occurs when participants modify their natural behavior in response to the fact that they are participating in a research study or the knowledge that they are being measured

Subject Roles

A participant's tendency to respond in a way that is expected to corroborate the investigator's hypothesis

in a study, a participant's tendency to respond in a way that is expected to refute the investigator's hypothesis

in a study, a participant's tendency to respond in a socially desirable fashion rather than truthfully

a participant's attempt to follow experimental instructions to the letter and to avoid acting on the basis of any suspicions about the purpose of te experiment

is any setting that is obviously devoted to the discipline of science. any room or any space that the subject or participant perceives as artificial

Modalities of Measurement