Beyond the B.A.S.I.C.S. Blog

Discrete Trial Data: First Response versus Continuous Collection

September 23, 2011


You’re observing an ABA therapist getting ready to start a session. He’s armed with a visual timer, a bag of reinforcers, and, of course, a clipboard full of paper listing all the targets he’ll be collecting data on. He may collect so much data that organizing and graphing it after his session actually takes longer than the session itself. So why does he spend so much time collecting continuous trial data when some other practices only collect first response data? Why must he analyze and record which steps in a seventeen step chained response his client missed when he had to prompt step 1? First response data is an efficient, easy way to track client progress, whereas continuous data collection is more energy intensive and more specific.

According to Cummings and Carr’s 2009 data collection study, clients mastered targets faster when therapists used first response data. A follow-up study by Lerman (et al) in 2010 agreed that discrete trial clients “learned faster” when mastery criteria for first response was set across two days. However, by increasing mastery criteria from two to three days, mastery levels dropped considerably – Lerman’s study actually found no difference in mastery speed between a 3-day first response criterion and a continuous collection criterion (standard practice is 80% across 2 days). A third study, done by Najdowski et al in 2009, established absolutely no difference between first response and continuous data regardless of mastery criterion. So which collection method is better? It’s a complicated answer. If you are lucky enough to have more staff than you know what to do with, and enough time to collect, process, and graph all that data (oh, and enough funding to pay your staff for non-billable tasks) – go for it! You’ll get what Cummings & Carr call a more sensitive data set that minimizes the impact of correct guesses and leads to a more stringent mastery criteria. Continuous data collection will tell you if a certain trial was instructional or in situ, and what level of prompt your client needed to give the correct response. You’ll be able to follow your data streams on a graph, and will therefore have a visual representation of your client’s progress (rather than a list of twenty-seven “no’s” followed by a “yes”).

On the other hand, let’s say insurance reimburses only for direct one-on-one therapist to client time, and then only for five hours a week. You have to use overhead to pay for team meetings, and your therapists don’t get paid at all to do things like write progress notes, fill out time sheets, or do monthly trainings. How many of those five hours do you want your therapist to spend writing things down, and how many do you want him to actually be working with the client? Does the specificity of data better serve you or your client? According to the above studies, if you set first response mastery criteria at 3 days, your results will be the same as collecting continuous data, and your client will get more ABA time (specifically, the amount of time you allot during each session for data processing).

Having been an ABA therapist for almost ten years now, I’ve used both data collection methods. I found first response easier, obviously, but sometimes struggled to recognize when my clients were making progress. I actually once asked for special permission to take more data (and graph it) because my client and I had been stuck on a specific skill for quite some time and I was getting just as frustrated as he was at our apparent lack of progress. Having the extra data, and being able to show him a slowly, steadily increasing graph line, helped both of us to stay motivated, and gave him the “proof” he needed that he was in fact learning. I was salaried at the time, so I was compensated for my extra time. Had I been an hourly employee, I may not have had the inclination to donate my time as freely (and it almost assuredly would have been donated time). It is unfortunate that funding plays any role in providing therapy, but it is nonetheless a truth. So. I suppose choosing a data collection method is much like choosing a car – you want the absolute best you can get for your investment. The studies show that, if done correctly, first response and continuous methods yield the same mastery results. If, then, you can afford the BMW, go for it! Having an on-board navigation computer and free maintenance for the life of your vehicle (or an average prompt level and the knowledge that it’s step 14 out of 17 that’s holding your client back) are great! A Honda with a hundred thousand miles on it, though, gets you to the grocery store the exact same way. Me? I’m a hybrid gal.

Sources: A Comparison of Methods for Collecting Data on Students’ Performance During Discrete Trial Teaching, Dorothea C. Lerman, Laura Harper, Taira Lanagan, Susie Balasanyan, and Lynn Williams, 2009. Comparison of Data-Collection Methods In a Behavioral Intervention Program for Children with Pervasive Developmental Disorders: A Replication, Adel C. Najdowski, Vardui Chilingarayan, Ryan Bergstrom, Doreen Granpeesheh, Susie Balasanyan, Barbara Aguilar, and Jonathan Tarbox, 2010. Evaluating Progress In Behavioral Programs For Children With Autism Spectrum Disorders Via Continuous And Discontinuous Measurement, Anne R. Cummings and James E. Carr, 2009.

Melissa L. Ruiz, BCaBA

BASICS ABA Therapy, LLC

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