The previous two measurement systems we identified were both examples of continuous measurement.
The next measurement systems we?ll look at are examples of discontinuous measurement systems. Discontinuous measurement methods are generally considered less valid than methods like frequency and duration recording. This is because they provide an estimate of the occurrence of a behaviour. While they may not be as accurate as continuous measurement methods, discontinuous methods are easier to implement ? especially when you are observing multiple people or multiple behaviors.
When using an interval recording system, you start by dividing an observation period into intervals. For example, we might divide an hour long observation into 12 minute intervals. When using Whole Interval Recording (WIR), behaviour is recorded as occurring only if it occurred for the entire length of the interval.
For example, Georgia is recording data on Adam?s behaviour that challenges. She marks that for the first two intervals, the behaviour occurred the entire time, but during the third the behaviour ended, so she didn?t mark the behaviour as occurring.
The thing to remember about whole interval recording is that the behaviour must occur for the whole interval in order to be recorded. If a behaviour starts half way through an interval, it is not recorded as occurring. If it stops half way through an interval, it is not recorded as occurring.
By contrast, Partial Interval Recording (PIR) is a related continuous measurement method. If the behaviour occurs at any point during the interval, the interval is marked as the behaviour having occurred.
For example, Deirdre?s supervisor has asked her to take data on Charlene?s self-injurious behaviour. Charlene engages in skin picking and Deirdre records her data using a partial interval recording system. Her data shows that Charlene engaged in skin picking for 14 out of the 20 intervals, but these instances did not always last for the entire interval length.
The key thing to remember about Partial Interval Recording, is that if the behaviour occurs at any point during an interval, we mark it as having occurred.