Chapter 3 of 912% of exam

Measurement, Data Display, and Interpretation

Domain C asks how behavior is defined, measured, checked and graphed, and how graphs are read. Expect calculations (rate, agreement), choices between measurement methods, and questions about what a data pattern means.

Defining and measuring behavior

Measurement starts with an operational definition that names observable topography. The outline distinguishes direct, indirect and product measures and asks you to measure occurrence and temporal dimensions. The dimension you measure should be the one that matters to the question being asked.

Operational definition

States what the behavior looks like in observable terms so two observers would score the same instances.

BACB BCBA Test Content Outline (6th ed.) C.1

Direct, indirect, product

Direct measures observe behavior as it happens; indirect measures rely on reports; product measures record lasting outcomes such as completed work.

BACB BCBA Test Content Outline (6th ed.) C.2

Rate

Count divided by observation time, which allows sessions of different lengths to be compared.

BACB BCBA Test Content Outline (6th ed.) C.3

Duration, latency, IRT

How long a response lasts; time from a stimulus to the response; time between two successive responses.

BACB BCBA Test Content Outline (6th ed.) C.4

Continuous and discontinuous measurement

Continuous methods capture every instance; discontinuous methods sample. Knowing the direction of each sampling method's error is more useful than memorizing a rule of thumb. The right choice depends on the dimension of interest and on what the observer can realistically do.

Partial-interval recording

Scores an interval if the behavior occurs at any point, so it can only add occurrence and tends to overestimate duration.

Powell, Martindale & Kulp, JABA 8 (1975)

Whole-interval recording

Scores an interval only if the behavior lasts throughout, so it tends to underestimate duration.

Powell, Martindale & Kulp, JABA 8 (1975)

Momentary time sampling

Records whether behavior is occurring at the end of each interval; practical when the observer cannot watch continuously.

BACB BCBA Test Content Outline (6th ed.) C.6

Quality of measurement

Validity asks whether the right dimension of the right behavior is measured; accuracy asks whether values match the true values; reliability asks whether the measure gives the same value for the same behavior. Interobserver agreement supports believability but does not establish accuracy or validity. Procedural integrity applies the same measurement logic to the people delivering the intervention.

Total count IOA

Smaller count divided by larger count, times 100.

BACB BCBA Test Content Outline (6th ed.) C.8

Agreement is not accuracy

Two observers can agree and both be wrong in the same way.

Johnston & Pennypacker, Strategies and Tactics of Behavioral Research

Procedural integrity

Measure whether the intervention was delivered as designed, including accuracy of each component and dosage.

BACB BCBA Test Content Outline (6th ed.) C.12

Displaying and interpreting data

Line graphs show change over time, bar graphs summarize discrete categories, and cumulative records show rate as slope. Visual analysis looks at level, trend and variability within and across phases. Decisions are made on the pattern of data, not on a single data point.

Cumulative record

Slope is response rate; a flat segment means no responses, and the line never goes down.

Skinner, A case history in scientific method (1956)

Steady state first

With highly variable or trending baseline data, extend baseline before introducing an intervention so its effect can be judged.

Sidman, Tactics of Scientific Research (1960)

Choose the graph for the question

Use an equal-interval line graph for ongoing decisions and a bar graph for summary comparisons across conditions.

BACB BCBA Test Content Outline (6th ed.) C.10

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