Summary: Counting and timing during a session gives you raw data. Summarizing turns that raw data into one number your BCBA can graph and read at a glance: a rate, a mean duration, a percentage, or a count. This page walks through the four you'll use most, with the actual arithmetic an RBT does between clients, plus when each one is the honest choice and when it quietly lies. The math is easy. Picking the right summary is the part the exam cares about.
You spend the session tallying clicks and timing episodes. Good. But nobody graphs a column of tally marks. At some point that raw data has to become a single number per session, and which number you report changes the story the graph tells. Report a count when you should have reported a rate and you can make a behavior look like it's exploding when it's flat. So this isn't busywork. Summarizing is where measurement either stays honest or goes sideways.
Most of the time your data sheet or your clinic's app does the arithmetic for you. You still have to understand it. You need to catch a number that looks wrong, explain a graph to a parent, and answer the exam questions that hand you raw data and ask for the summary. So we'll do the math by hand.
The four summary measures you'll actually use
There are really four you reach for over and over: count, rate, mean duration, and percentage. Each one compresses a pile of raw observations into a single value. The trick is that each one assumes something about your data, and when that assumption breaks, the summary misleads.
Here's the shape of each before we dig in:
That's the free preview of Data Calculation and Summarization. The complete guide, plus all 851 practice questions and 3 full exams, is in the study pack and the book.