Chapter 3: Constructs and Operational Definitions

Behaviour measure

a manner in which researchers can observe constructs in overt behaviours such as laughing, playing, eating, sleeping, arguing or speaking. Behavioural measures provide researchers with a vast number of options making it possible to select the behaviours that seems to be best for defining and measuring the construct.

Validity

a measurement procedure is the degree to which the measurement process measures the variable that it claims to measure.

Operational definition

a procedure for indirectly measuring and defining a variable that cannot be observed or measured directly. An operational definition specifies a measurement procedure (a set of operations) for measuring an external, observable behaviour , and uses the resulting measurements as a definition and measurement of the hypothetical construct.

Theory

a set of statements about the mechanisms underlying a particular behaviour. Theories help organize and unify different observations of the behaviour and its relationship with other variables. A good theory generates predictions about the behaviour.

Face validity

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

Demand characteristic

any of the potential cues or features of a study that (1) suggest to the participants what the purpose and hypothesis is, and (2) influence the participants to respond or behave in a certain way

Laboratory

any setting that is obviously devoted to the discipline of science; it can be any room or space that the subject/participant perceives as artificial

Double-blind

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

Convergent validity

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

Divergent validity

demonstrated by showing little or no relationship b/w the measurements of two different constructs

Predictive validity

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

Concurrent validity

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

Test-retest reliability

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

Physiological measure

examine the physiological manifestations of the underlying construct; example: fear = increased heart rate

Constructs

hypothetical attributes or mechanisms that help explain and predict behaviour in a theory

Parallel-forms reliability

if alternative versions of the measuring instrument are used for the two measurements during test-retest reliability

Split-half reliability

obtained by splitting the items on a questionnaire or test in half, computing a separate score for each half, and then calculating the degree of consistency b/w the two scores for a group of participants

Reactivity

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

Experiment bias

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

Field

place that the participant/subject perceives as a natural environment

Construct validity

requires that the scores obtained from a measurement procedure behave exactly the same as the variable itself. Construct validity is based on many research studies that use the same measurement procedure and grows gradually as each new study contributes more evidence.

Single-blind

researcher does not know the predicted outcome

Self report measure

self-reported; primary advantage is that the most direct way to assess a construct

Reliability

stability of consistency of the measurement; if the same individuals are measured under the same conditions' reliable measurement procedure produces identical (or nearly identical) measurements.

Ceiling effect

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

Floor effect

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

Apprehensive subject role

the participants are overly concerned that their performance in the study will be used to evaluate their abilities or personal characteristics; they are trying to place themselves in a desirable lightly responding in a socially desirable fashion, instead of truthfully

Faithful subject role

these participants attempt to follow instructions to the letter and avoid acting on any suspicions that they have about the purpose of the study

Negativistic subject role

these participants have identified the hypothesis of the study and are trying to act contrary to the investigators hypothesis

Good-subject role

these participants have identified the hypothesis of they study and are trying to produce the responses that support the investigators hypothesis

Positive relationship

two measurements change together in the same direction

Negative relationship

two measures change in opposite directions so that people who score high on one measure tend to score low on the other.