Chapter 6: Making Systematic Observations

Reliability

A measure’s ability to produce similar results when repeated measures are made under identical conditions.

Validity

The extent to which a measure measures what you intend it to measure.

Precision

The degree to which repeated measurements under unchanged conditions show the same results.

Test-retest reliability

Administering the same test twice to the same individuals to assess consistency over time.

Parallel-forms reliability

Establishing reliability by administering alternate forms of a questionnaire repeatedly.

Split-half reliability

Assessing reliability by splitting a questionnaire into two parts and correlating responses.

Face validity

How well a measurement instrument appears to measure what it is designed to measure.

Content validity

How adequately a test samples the knowledge, skills, or behaviors that it is intended to measure.

Criterion-related validity

The ability of a measure to produce results similar to established measures of the same variable.

Concurrent validity

The validity established by showing that scores on a test correlate with another measure taken at the same time.

Predictive validity

The ability of a measure to predict some future behavior.

Construct validity

Validity that applies when a test measures a theoretical construct.

Nominal scale

A measurement scale that classifies variables into distinct categories without a numeric value.

Ordinal scale

A measurement scale that ranks values according to quantity but does not specify the degree of separation.

Interval scale

A measurement scale with equal intervals but no true zero point.

Ratio scale

A measurement scale with equal intervals and a true zero point, indicating the absence of the measured attribute.

Range effects

A situation where a variable reaches an upper or lower limit, limiting the ability to detect differences.

Behavioral measure

A measure of a subject’s actual behavior in a situation, such as frequency of actions.

Physiological measure

A measure of bodily functions, such as heart rate or blood pressure.

Self-report measure

A measure where participants report their own behaviors, feelings, or thoughts.

Implicit measure

A measure that assesses attitudes or biases that are not under conscious control.

Demand characteristics

Cues provided by researchers that may inadvertently inform participants about the study's purpose.

Experimenter bias

When a researcher’s expectations influence the participants’ behavior or the study's outcome.

Single-blind technique

An experimental design where the participant is unaware of their treatment status.

Double-blind technique

An experimental design where both the participant and experimenter are unaware of treatment assignments.

Pilot study

A small-scale version of a study used to test feasibility, time, cost, and adverse events.

Manipulation check

A test to determine whether the independent variable has been successfully manipulated.

Margin of error

The uncertainty surrounding estimates in population studies.

Ecological validity

The degree to which research findings can be generalized to real-world settings.

Sensitivity

The ability of a measure to detect changes or effects in a variable being studied.

Ceiling effect

A situation where data is clustered at the upper limit of a measurement scale.

Floor effect

A condition where data is clustered at the lower limit of a measurement scale.

Type I Error

Incorrectly rejecting a true null hypothesis (false positive).

Type II Error

Failing to reject a false null hypothesis (false negative).