Data Grouping with Variable Files

A variable file groups codes for analysis. It can be made before, during, or after coding. The variable file also indicates which type of coding was used (continuous for discrete events or start/stop for overlapping events). One dataset may be analyzed with multiple variable files, or one variable file may be used to analyze several datasets. This feature also flags output with possible inaccuracies by one of a number of variable error messages. The Statistical Analysis methods in OCS can use variables to calculate duration and overlap information.

Variable files can be four different types:

Start/Stop codes

Start and Stop coding employs two codes for each event. One code turns that event on or active, and the other code turns it off or not active. Here is an example of a start and stop code:



One benefit of variables are they can overlap other variables and be nested inside others, if tracking two events that are nested such as holding a pen and writing. For example, writing cannot be done without holding a pen, but writing isn't always being performed while a pen is being held.

Start only codes

Start only codes are very similar to start/stop codes except that they use only one code to represent on or active. When a start only code is entered, the previous code is turned off, or not active, and the current code is on, or active, until another code is entered. This kind of coding can be useful when observing activities that don't overlap. An example for start only coding would be keeping track of when someone was awake or asleep, since these activities cannot happen at the same time.

Stop only codes

Stop only codes are similar to start-only codes except that a single code is use to turn the code off or not active. The code turned off will have been active since the time the last code was entered. This kind of coding is useful when recording an event that will only be known when it ends. An example for stop only coding would be observing kids at play. What the kids were doing won't be known until after it's done, and by that time they would already be starting something else.

Boolean Variables

Boolean variables combine regular variables to extend their range. Boolean variables aren't entered manually by the user, the variable is generated automatically when certain combinations of variables occur. A Boolean variable is generated when two variables are both active, when only one is active or even when both are not active. Once defined Boolean variables are used automatically without user intervention.