Overview of the Measurement Section
The Measurement section represents approximately 21% of the BCBA exam. It tests your ability to select appropriate measurement procedures, collect and graph data accurately, evaluate data using visual analysis, and use single-subject experimental designs to demonstrate functional relationships.
Key Topics
Measurement Procedures
You must understand both continuous and discontinuous measurement procedures. Continuous measures include frequency/rate, duration, latency, and interresponse time. Discontinuous measures include partial interval recording, whole interval recording, and momentary time sampling. Know when to use each method and how to calculate results.
Interobserver Agreement (IOA)
IOA measures the consistency between two or more independent observers. Methods include total count IOA, exact agreement IOA, trial-by-trial IOA, and interval-by-interval IOA. You should know how to calculate each type, when each is appropriate, and acceptable IOA thresholds (generally 80% or higher).
Data Display and Graphing
Standard graphing conventions in ABA include line graphs with connected data points within conditions, phase change lines between conditions, condition labels, and appropriate axis labels and scaling. Understand cumulative records, standard celeration charts, and how to display different types of data appropriately.
Single-Subject Experimental Designs
The exam tests knowledge of reversal (ABAB) designs, multiple baseline designs (across participants, settings, or behaviors), changing criterion designs, multielement (alternating treatments) designs, and combined designs. You must understand the strengths, limitations, and appropriate applications of each design.
Visual Analysis
Visual analysis involves examining graphed data for level, trend, and variability within and across conditions. You should be able to identify stable baselines, predict data paths, verify treatment effects, and replicate findings. This skill is fundamental to data-based clinical decision-making in ABA.
Study Strategy
Practice reading and interpreting graphs. The exam frequently presents graphed data and asks you to identify the design, evaluate the results, or make a clinical decision based on the data. Use BCBAprep flashcards to drill measurement terminology and practice calculating IOA and measurement results.